Dual-GPU Frame Generation with Lossless Scaling (RTX 3070 + GTX 1080)
Overview and Dual-GPU Frame Generation Mechanism
Lossless Scaling (LS) is a software tool that can inject AI-driven upscaling and frame generation into games, even if the game doesn’t natively support technologies like DLSS 3 or FSR 3. Recent versions of LS introduced a Frame Generation (FG) feature that works universally across games. In a dual-GPU setup, LS can offload the frame generation and upscaling tasks to a secondary GPU while the primary GPU focuses on rendering the game. This effectively allows older or secondary GPUs to act as a “frame interpolator,” inserting extra frames to boost framerate without burdening the main graphics card (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware) (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware). The RTX 3070 (Ampere) in this scenario serves as the render GPU (running the game), and the GTX 1080 (Pascal) serves as the LSFG GPU (performing Lossless Scaling’s upscaling and frame interpolation).
In practice, the game renders at a chosen base resolution and framerate on the RTX 3070, and each frame is passed to the GTX 1080. The LS software running on the secondary GPU then upscales the frame (if rendering at a lower resolution for performance) and generates intermediate “fake” frames between the real frames, effectively doubling (or even tripling, etc.) the displayed framerate. The primary benefit of this design is that frame generation becomes “free” from the perspective of the main GPU’s workload – all the heavy lifting of AI-based interpolation is on the secondary card (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware). As long as the secondary GPU is sufficiently powerful for the target resolution and FPS, the primary GPU sees almost no performance hit from LS’s frame gen. This approach was demonstrated by the community and confirmed in reviews: using a secondary GPU for LS Frame Generation can achieve higher FPS with minimal impact on the primary GPU’s utilization (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware). It’s essentially a way to leverage an older GPU (or an integrated GPU) to get DLSS 3-like frame insertion on systems that don’t have a latest-gen card.
How LS leverages the two GPUs: The key is in how Windows and LS are configured. The display output must be driven by the secondary GPU, so the monitor is physically connected to the GTX 1080 in our example. This allows the rendered frames from the RTX 3070 to be handed off to the 1080 via system memory/PCIe, and then the 1080 draws the final image to the screen. If the monitor were attached to the primary GPU instead, the processed frames would need to be copied back again, which is very inefficient (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Thus, one best practice is connecting your monitor to the LSFG (secondary) GPU to avoid needless round-trips (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). In software, you then instruct the OS and Lossless Scaling which GPU does what: the game will be forced to use the high-performance GPU (3070) for rendering, and the Lossless Scaling app will be set to use the GTX 1080 for its computations. (On Windows 11 this is straightforward via Settings > System > Display > Graphics > Default high performance GPU = RTX 3070 (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). On Windows 10, it can be done via registry or per-app GPU preferences since the UI only shows one “High Performance GPU” option by default (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!) (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!).) In the LS GUI, you simply select the “Preferred GPU” for frame generation as the secondary card (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!).
When configured properly, LS intercepts the game’s output frames (using DXGI desktop duplication or similar capture) and processes them on the second GPU. The result is that the RTX 3070 produces the same number of “real” frames as it normally would, and the GTX 1080 generates additional frames in between. This multi-GPU frame pipeline is synchronized such that the visual output is a higher frame rate stream. The overhead on the main game is mostly limited to a bit of CPU and bus bandwidth to copy frames to the second GPU – GPU render time on the 3070 remains roughly the same as it would without frame generation (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions). In summary, Lossless Scaling’s dual-GPU feature lets you re-purpose a Pascal (or any) GPU as an AI frame generator, bringing features akin to NVIDIA’s Frame Generation or AMD’s Fluid Motion Frames to virtually any game on your system.
Performance Impacts and User-Reported Experience
A dual-GPU LSFG setup can deliver substantial framerate boosts in games, but performance depends on the balance between your GPUs and the overhead of copying frames. In the ideal case (primary GPU near fully utilized, secondary GPU capable), users have reported significant FPS gains with almost zero performance loss on the main GPU. For example, in one test Assassin’s Creed Odyssey was run at 1440p Ultra with an RTX 4060 Ti as the renderer and a GTX 1660 Super as the LSFG card. The dual-GPU configuration achieved ~70 FPS, versus ~54 FPS when the 4060 Ti alone handled both rendering and frame generation (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Notably, the RTX 4060 Ti’s utilization stayed around ~97% in both cases, indicating the extra 16 FPS came “for free” from the second GPU offloading the frame interpolation. This showcases the core advantage: higher frame rates without increasing the primary GPU load.
However, real-world performance can vary. Latency: In terms of input latency, frame generation inherently adds a small amount of delay (since a generated frame is displayed instead of a real, updated frame). Data from the LS developer and community indicates that using LSFG adds roughly the latency of one extra frame on top of the base rendering latency (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Page 7 | Beyond3D Forum) (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Page 7 | Beyond3D Forum). This is very similar to NVIDIA DLSS 3 FG’s behavior – essentially, if you double the framerate from 40 FPS to 80 FPS via interpolation, your input lag will correspond roughly to the 40 FPS baseline plus one frame (so not a 2× reduction in latency, but also not a massive lag spike). In practice, that means the gaming feel remains responsive as long as your base FPS is decent. The generated frames do not reduce input lag, but they greatly improve perceived smoothness. Many users report that in casual or single-player games, the added fluidity is well worth it, and the input response still feels tied to the real frame rate (e.g. if a game runs 45 FPS base, it still only samples input 45 times per second even if 90 FPS is displayed) (Wouldn't using LSFG increase input lag? :: Lossless Scaling General Discussions). For competitive twitch-sensitive games, interpolated frames (whether DLSS FG or LSFG) are less ideal, but LSFG is typically used for visual enhancement in non-competitive titles where extremely low latency is not the top priority (Wouldn't using LSFG increase input lag? :: Lossless Scaling General Discussions) (Wouldn't using LSFG increase input lag? :: Lossless Scaling General Discussions). It’s also possible to use NVIDIA Reflex (if available in a game or via driver) to minimize the base latency and partially offset any added delay (Wouldn't using LSFG increase input lag? :: Lossless Scaling General Discussions), though Reflex can’t speed up the generated frames’ inherent delay. Overall, user feedback on latency with dual-GPU FG is positive – some have even measured that LSFG on a second GPU can have lower latency than native DLSS3 on a single GPU in certain cases (How good/bad is the latency with dual GPU ? : r/losslessscaling) (likely because the primary GPU isn’t bogged down and can maintain higher base FPS, plus LSFG can be tweaked). The key point is that the feel of input corresponds to your real FPS; frame generation doesn’t worsen this baseline, it just doesn’t improve it (and adds roughly ~1 frame of lag for the visuals, which is hardly noticeable when running well above 60 FPS).
Throughput and visual quality: The GTX 1080 will be working hard to generate frames, and its ability to keep up will depend on resolution and desired frame rate. LS offers Quality vs Performance modes for frame generation – these likely trade off interpolation fidelity vs. speed. Users note that at higher resolutions (1440p, 4K) or very high target FPS, the secondary GPU can become a bottleneck if it’s not powerful enough (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). If the LSFG GPU cannot generate frames as fast as needed, you may see reduced “generated FPS” or irregular frame pacing (the app may report doubled FPS, but some frames get dropped before display because they missed the v-sync/window, resulting in stutter). To avoid this, it’s recommended to cap the game’s framerate to a level the second GPU can reliably double. Many users use RTSS or in-game limiters to lock the base FPS to, say, half of the monitor refresh (e.g. cap at 72 FPS on a 144 Hz display, to target 144 FPS output). This gives the secondary GPU a consistent target. For example, one LSFG user of Cyberpunk 2077 noted the game’s built-in FPS limiter was handy to find a stable cap that the PC could “always handle” for smooth frame generation (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). Similarly, another user testing DayZ found that uncapped frames led to the secondary GPU dropping behind (100+ FPS base was too much), but capping to 75 FPS base yielded a very smooth experience with interpolated frames up to ~150 FPS (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). Adaptive FG vs Fixed FG: Lossless Scaling 3.x introduced an “adaptive” frame gen mode that tries to dynamically insert frames when possible (not always a fixed 2x). Some anecdotal reports (e.g. Far Cry 3 tests) suggest the adaptive mode can introduce more input lag than the fixed 2× mode (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). In those cases, using a fixed multiplier (e.g. always generate 1 extra frame per real frame) felt “smoother and snappier” than adaptive insertion, at the cost of not maximizing FPS during easier scenes (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). It’s worth experimenting in the LS settings to see which mode feels best; results can vary by game.
Visually, the quality of generated frames from LSFG is reported to be quite good – approaching the quality of DLSS Frame Generation or AMD’s Fluid Motion Frames. It does not require motion vectors from the game engine, instead relying on its own optical flow or AI interpolation algorithms (the developer has hinted at techniques like RIFE or similar under the hood). The artifact level is generally low at high frame rates, but like all interpolation, you might occasionally notice minor motion artifacts (e.g. on very fast-moving objects or UI elements). Overall, users praise the “great quality image” for the added frames, with minimal artifacting in most games (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions). In fact, one advantage of LSFG is that it can be used in conjunction with in-game TAA or DLSS without interfering – it simply takes the final composed image and generates between-frames, so it will even interpolate things like particle effects or post-processing that an engine-based solution might not. As a bonus, the LS tool can also apply upscaling (FSR, etc.) at the same time, so you can render at a lower res + get frame gen concurrently. This stacking of techniques can yield enormous performance uplifts (e.g. some enthusiasts run a game at 50% res with LSFG 4× on top, effectively getting 4x the FPS at near-native visual quality when tuned correctly (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Page 7 | Beyond3D Forum)). Just keep in mind each extra step introduces load on the secondary GPU.
Performance hits and bottlenecks: The primary overhead in this dual-GPU approach is the PCIe bus communication and the load on the secondary GPU. If the PCIe link is too slow, or the secondary GPU is maxed out, you can get diminishing returns or even negative returns. A few users have encountered scenarios where offloading to a second GPU actually hurt performance – these cases usually involve a very powerful primary GPU and a much weaker secondary, or insufficient PCIe bandwidth. For example, one user tried pairing an RTX 4080 with a GTX 1080 for 1440p upscaling+FG and found that the performance was worse with the dual setup: both GPUs went to ~80% usage and the frame rate dropped compared to just the 4080 alone (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions). In that instance, the 4080 was so strong that it could handle the upscaling internally at 60 FPS with plenty of headroom, and adding the 1080 introduced overhead (the X470 board forced both GPUs to run at PCIe 3.0 x8, and the 1080 simply couldn’t process as fast as the 4080 could) (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions) (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions). The lesson is that dual-GPU FG helps most when the primary GPU is the limiting factor and the secondary can keep up with the necessary frame processing. If your primary GPU is already underutilized in a game (CPU bound or just very fast), forcing it to wait for a slower card can bottleneck you. In the case of an RTX 3070 + GTX 1080, the 3070 is indeed significantly faster for rasterization; in lighter games or low resolution, the 1080 could become the limiting factor. But in GPU-heavy games (e.g. Cyberpunk with RT, or future Path of Exile 2 high settings), the 3070 will likely be maxed out rendering ~60 FPS or less at high res, and there the 1080 can potentially double the output smoothly. Always monitor the utilization: if the secondary GPU is pegged at 100% and dropping interpolated frames, you may need to lower the load (reduce resolution or frame cap). On the other hand, if the secondary GPU isn’t fully utilized, that’s good – it means it has headroom or you might even try a higher frame-gen multiplier. Some users with excess secondary GPU power choose to undervolt/underclock the secondary card to save energy and heat, since running at 100+ FPS interpolation can make even a GTX 1080 draw significant power continuously (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!).
Compatibility with Modern Titles (Cyberpunk 2077, Path of Exile 2, etc.)
One of the strengths of Lossless Scaling’s approach is that it is game-agnostic. It captures frames at the output level, so it should work with virtually any game that can run in a windowed or borderless window mode (since LS needs to overlay or capture the frame buffer). This includes modern titles like Cyberpunk 2077 and upcoming games like Path of Exile 2. In fact, community testers have explicitly reported good results with these games:
Cyberpunk 2077: Despite having its own (proprietary) frame generation for RTX 40-series, CP2077 can also be used with LSFG on older GPUs. Users have noted that LSFG “works very well” in Cyberpunk (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). The key is to use the game’s frame limiter or RTSS to cap the base FPS to a stable value that the secondary GPU can double. Cyberpunk’s demanding visuals make it a perfect candidate – for example, a 3070 might only manage ~45 FPS with ray tracing in 4K, but paired with a second GPU via LSFG, you could get an interpolated ~90 FPS for much smoother output. There were no specific compatibility issues reported; LSFG can inject just fine in Cyberpunk (which runs in DX12). One should disable the in-game DLSS Frame Generation if trying LSFG (they wouldn’t be used together anyway), but DLSS Super Resolution or FSR can be used in tandem with LSFG if desired.
Path of Exile 2: PoE2 is still in development (targeting a 2024-2025 release), but early tests indicate LSFG can be used. One user managed to get LSFG working with PoE2’s preview/build and saw roughly a 15–20 FPS improvement in their case (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). This suggests that PoE2 (which is expected to have its own upscaling options and maybe DLSS) doesn’t prevent LS from working. It’s likely PoE2, being based on a new engine, will support windowed/borderless modes where LSFG can hook in. Note: If PoE2 includes an anti-cheat (since PoE has competitive economies), it’s something to watch – however, LS operates similarly to an external overlay and should be as acceptable as using something like ReShade or OBS capturing. As always, one should verify any anti-cheat or EULA, but generally LS is used for visual enhancement and is not known to be flagged (for example, players have used it in Escape from Tarkov and other online games as noted on the Steam community, without issue).
Other modern titles: The community has compiled a large list of games tested with LS Frame Generation. Most DX11/DX12/Vulkan games work out of the box as long as you run in borderless window (LS’s new DXGI capture can even tie to the game’s framerate to improve pacing (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Beyond3D Forum) (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Beyond3D Forum)). For older games that only support exclusive fullscreen, you may need to force windowed mode (e.g. with Alt+Enter or config tweaks) for LSFG to work (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). The good news is many modern titles have borderless window modes by default. Games like Starfield, Red Dead Redemption 2, Assassin’s Creed Valhalla, Fortnite, etc., all have been shown to work with LSFG. Even emulator and older engines (DX9, etc.) can often be captured by LS if running through the desktop compositor. There are a few edge cases: if a game has an internal fps cap or V-sync that you can’t disable, it might limit the benefit (since LS can’t exceed a game’s own cap except by duplicating frames, which still won’t go beyond the monitor’s refresh). Also, some very fast-paced competitive games might not be ideal simply because the fake frames could throw off timing (for example, some players might avoid it in Counter-Strike or similar, but others have tried it in games like Overwatch just for experimentation).
From a software compatibility standpoint, LSFG doesn’t require any special driver beyond a working graphics driver, and it supports Nvidia, AMD, or Intel GPUs. It also supports mixing vendors (you could use an NVIDIA primary and an AMD secondary or vice versa). The LS tool itself is distributed via Steam and updated frequently – as of early 2025 (v3.x), it’s stable and feature-rich. Cyberpunk 2077 and PoE2 specifically should benefit greatly because they are GPU-bound. As an aside, PoE2 is known to include its own in-game upscaling (DLSS) but not frame generation for non-40 series; LSFG can thus serve as a way to get frame interpolation in PoE2 on a 3070. Meanwhile, CP2077 does have native FG but only on 40-series – with LSFG, a 3070 + 1080 setup can mimic that and still achieve smooth output.
It’s always a good idea to check the LS community forums for any game-specific tips. For example, some games might need the “swap effect” changed in LS settings or certain vsync behavior to avoid tearing. The community guide of working games includes notes per title. So far, no show-stopping incompatibilities with major modern titles have been reported. In summary, compatibility is broad, and both Cyberpunk 2077 and Path of Exile 2 are confirmed to work with dual-GPU Lossless Scaling FG setups, providing substantial performance/visual benefits in each.
System Configuration, PCIe Considerations, and BIOS/Driver Setup
To successfully run a dual-GPU frame generation setup, you need to ensure your hardware and software are configured correctly. Below are the important configuration points and best practices:
Motherboard & PCIe Bandwidth: Your motherboard must support two GPUs installed simultaneously (an x16 slot plus a second slot). More critically, the second slot should have at least a PCIe 3.0 x4 connection available (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Bandwidth is crucial because each frame rendered by the main GPU has to be copied over this bus to the secondary GPU every refresh. A PCIe 3.0 x4 link provides ~4 GB/s which is typically enough for 1080p or 1440p frame transfers, but can become a bottleneck at 4K or very high FPS. The community warns that anything less (e.g. PCIe 3.0 x1 or older PCIe 2.0) will likely choke the performance and cause stuttering and blurriness (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). If you plan to use 4K resolution or higher refresh rates, a PCIe 4.0 x4 (or better) link for the secondary GPU is recommended (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). For instance, on a newer motherboard that might mean the secondary card can run at PCIe 4.0 x4 from the chipset, or if using an older board, the primary and secondary might run at 3.0 x8 each (which is equivalent bandwidth to 4.0 x4). Ensure in your motherboard BIOS that any settings for bifurcation or multi-GPU are enabled if needed (most boards auto-configure the lanes when a second GPU is inserted, sometimes dropping the primary to x8 and giving x8 to the secondary; consult your board manual for the lane configuration). It’s also advisable to enable “Above 4G Decoding” in BIOS when using multiple large BAR devices (GPUs), as is common for multi-GPU setups, to ensure the system can map their memory properly.
GPU Placement and Cooling: Install the RTX 3070 in the primary (usually top x16) slot and the GTX 1080 in the secondary slot. Since the monitor will be attached to the 1080, it effectively becomes the “primary display adapter” in Windows once booted. Some BIOS/UEFI firmwares have an option for initial display output (PEG slot selection); you can usually leave it on auto, but if you find you get no POST screen, you might set the initial display to the slot with the 1080. Both GPUs will generate heat – make sure your case has good airflow because the secondary card will be under constant load during gaming as well. Check that your PSU is sufficient to power both GPUs at full tilt (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). A RTX 3070 plus GTX 1080 could draw ~400W together (plus CPU etc.), so a quality PSU of ~750W or higher is recommended for safe overhead. If needed, you can limit the power target on the secondary GPU in NVIDIA Control Panel or MSI Afterburner; many users undervolt or set a frame cap such that the older card doesn’t run 100% all the time to reduce power draw (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!).
Connecting the Monitor: Plug your monitor(s) into the secondary (LSFG) GPU, not the primary. This is crucial for performance (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). By having the GTX 1080 output to the display, the rendered frames only travel one direction (3070 -> 1080 -> display). If you were to connect the monitor to the 3070 instead, the 3070 would send frames to 1080 for processing and then those would have to be sent back to 3070 for display, incurring a huge bandwidth and latency penalty (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). So, rearrange your cables such that the card doing frame-gen drives the screen. If you use multiple monitors, ideally keep your game’s primary display on the LSFG GPU. (Having a second monitor on the other GPU is possible but be mindful that if you run the game on a monitor that isn’t attached to the LSFG GPU, you defeat the purpose. Some advanced users do run two monitors, one on each GPU, for other reasons, but for simplicity it’s best to run the game on the LSFG GPU’s output.)
Operating System Settings (GPU Preferences): By default, Windows may try to run the game on the GPU that’s attached to the display (which now is the GTX 1080). We need to override that so the game actually runs on the RTX 3070. In Windows 10, this can require a registry tweak because the UI might not list both GPUs for app preferences (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). The Steam guide outlines adding a key
HighPerfAdapter=GPUIDinHKEY_CURRENT_USER\Software\Microsoft\DirectX\UserGpuPreferencesto force a specific GPU as the “High Performance” device (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Essentially, you find the PCI ID of your RTX 3070 and set it as the global high-perf GPU. After a reboot, you can then assign programs (or the system default) to use that GPU for rendering. In Windows 11, Microsoft made this easier: go to System > Display > Graphics > Default Graphics Settings and choose the RTX 3070 as the “Default high performance GPU” (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). This tells Windows that any app requesting high-performance graphics (like your games) should preferentially use the 3070. Additionally, for Windows 11 or 10, you can specifically add your game’s .exe in the Graphics Settings panel and set it to use the High Performance GPU (the 3070) and add the Lossless Scaling app and set it to “Power Saving” (which would be the 1080 if the 3070 is high-perf by default). This step ensures the game renders on the correct GPU while the LS software can be running on the other.NVIDIA Control Panel Settings: If both GPUs are NVIDIA (as in this case), open the NVIDIA Control Panel > 3D Settings. One setting to change is “OpenGL rendering GPU” – set that to the RTX 3070 (the rendering GPU) (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). This is mostly relevant for OpenGL games (or Vulkan, which sometimes piggybacks on that setting) and older titles like Minecraft; it ensures even if Windows might not pick the right GPU for OGL contexts, the driver will use the 3070 for rendering those. Also, make sure G-SYNC/FreeSync is configured properly for the monitor on the 1080 if you use VRR. You might also want to disable NVIDIA’s “Low Latency Mode” or limiter for the LS app if it shows up, to avoid any conflicts – but generally it’s fine to leave default. No special driver is needed beyond having a driver that supports both cards (any recent NVIDIA driver will support both Pascal and Ampere GPUs concurrently).
Lossless Scaling App Settings: In the Lossless Scaling tool, under the GPU and Display section, set the “Preferred GPU” to your secondary (GTX 1080) (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Double-check that LS is indeed running on the correct GPU (the app might show an indicator of which it’s using, or you can watch GPU usage in Task Manager – when frame generation is on, the secondary GPU usage should spike). Select your desired Frame Generation multiplier (usually 2× for one interpolated frame per real frame, though LS also has higher options like 3×, 4× etc., and an “auto” mode). As a starting point, use 2× (Fixed) which doubles the FPS. You may also set the upscaling algorithm if you plan to render at a lower resolution – for example, you can choose FSR, NIS, Lanczos, etc. or even “None” if you’re rendering at full res and only want frame-gen. Many people use Scaling Type: “Auto” and Scaling Mode: “Off” to let LS just do frame gen without extra scaling (if the game is already at target res). Ensure V-Sync in-game is off (it’s better to control sync via LS or driver in this scenario to avoid the game capping its own FPS). LS has its own V-sync option; you can experiment with it. Often, using borderless window + in-game V-sync off + driver V-sync off + maybe LS V-sync on yields good frame pacing, but this can depend on the game. The Steam community guide for frame-gen includes specific tips per game in some cases (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]) (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]).
PCIe and Power Management Tweaks: It’s a good idea to disable PCIe power-saving features that could throttle the link. In Windows, set your Power Plan to “High Performance” or “Ultimate Performance” (or in Windows 11, in Graphics Settings enable “Hardware-accelerated GPU scheduling” which might help slightly in multi-GPU transfers). In your motherboard BIOS, look for settings like “PCIe ASPM” or “Link State Power Management” and consider disabling those for the slots – one Reddit user noted that disabling PCIe link power management in BIOS fixed issues of fluctuating clocks on the secondary GPU during LSFG use (Dual GPU problem : r/losslessscaling - Reddit) (Dual GPU LSFG is a lifestyle. : r/losslessscaling - Reddit). Essentially, you want the secondary GPU to stay engaged at full speed. Also, if your secondary GPU is in a slot that shares bandwidth (e.g., with an M.2 slot), be mindful not to saturate that by, say, a PCIe 4.0 NVMe running at the same time if it shares lanes. Usually, it’s fine, but check if your mainboard manual indicates any lane-sharing between the M.2 and the second PCIe slot (some boards reduce an NVMe to x2 if the second GPU is used, etc.). The goal is to maintain at least that x4 link at full speed continuously.
Driver Stability: Running two GPUs of different generations on the same NVIDIA driver generally works without issue – NVIDIA’s drivers support multi-adapter setups (they even support SLI between identical GPUs, but here we are not using SLI – the cards operate independently). Make sure to be on a relatively recent driver that still supports Pascal (NVIDIA did continue support for 10-series through 2024 in their driver updates). No special profiles exist for LSFG; it just appears as a regular application doing compute. If you encounter any black-screen in the LS app itself when starting frame generation, one tip from the changelog is to ensure LS is running on the same GPU that’s connected to the monitor by default (power saving mode as mentioned) (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Beyond3D Forum). Typically, if you followed the steps above, that condition is met.
In short, the system config needs to maximize data transfer rates between GPUs and assign roles properly. The RTX 3070 should be the one rendering the game, the GTX 1080 the one outputting to display and doing LSFG, and the connection between them (PCIe) should be as fast as possible with no power hiccups. Following these guidelines will yield the best performance and smoothness.
Known Issues, Bottlenecks, and Limitations (Ampere + Pascal Pairing)
When mixing an Ampere and Pascal GPU for this purpose, there are a few known limitations and potential bottlenecks to be aware of:
No Optical Flow Accelerator on Pascal: The RTX 3070 (Ampere) has dedicated optical flow hardware (which NVIDIA uses in DLSS 3 frame gen), but the GTX 1080 (Pascal) predates that and does not have such units. Lossless Scaling’s algorithm likely uses a general-purpose approach (possibly DirectX Optical Flow or a custom shader/tensor model). This means the 1080 will be using its CUDA cores (or potentially its limited tensor/FP16 throughput) to calculate motion vectors and generate frames. Pascal’s GPUs have relatively poor FP16 performance (GTX 1080 performs FP16 at 1/64 the rate of FP32), and no tensor cores. By contrast, an RTX card or AMD RDNA2/3 card can handle half-precision or AI workloads more efficiently. In practice, this manifests as lower maximum frame-gen capacity on Pascal GPUs for a given power. The community observed that AMD GPUs tend to outperform NVIDIA GPUs of similar raster strength in the LSFG role – for example, an AMD RX 5600 XT could generate more FPS via LSFG than an RTX 3060, and even an entry-level RDNA2 like RX 6500 XT often outclassed a GTX 1660 Super in frame-gen (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). They theorize it’s because of better FP16 support on those cards (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). What this means for an Ampere+Pascal pair is that your GTX 1080 might be the limiting factor in high-end scenarios. It’s a strong card for its time, but newer interpolation algorithms love tensor/AI hardware. Don’t expect the 1080 to double 4K 120FPS or something extreme – it will likely cap out earlier. For instance, a GTX 1080 is more comparable to a 5600 XT/5700 in compute, which users report can handle around 1440p @ 80→160 FPS in quality mode before hitting limits (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). If you push beyond its capabilities, the generated frames might start dropping (LS will show it’s trying, but your actual displayed FPS won’t reach the 2× target). So, one limitation is simply the performance ceiling of the 1080 in this role.
PCIe Generation Mismatch: The RTX 3070 supports PCIe 4.0, whereas the GTX 1080 is PCIe 3.0. In a mixed setup, they’ll operate at PCIe 3.0 speeds on that link (since the 1080 can’t do 4.0). If your motherboard is newer (PCIe 4.0 capable), the 3070 might run at 4.0 x16 in primary slot, and the 1080 at 3.0 x… whatever lanes secondary has. If it’s an older board, both might be at 3.0. The key is, as discussed, you have enough lanes. But the gen mismatch just means you can’t take advantage of the 3070’s PCIe 4.0 bandwidth for this – it will down-negotiate to 3.0. In most cases this is fine (PCIe 3.0 x8 or x4 can do the job at moderate resolutions), just be aware that the bus could become a bottleneck if you try something like 4K at very high FPS. The symptom of hitting the PCIe limit is typically both GPUs not fully utilized but frame pacing is bad. If you suspect this, moving to a platform that allows 4.0 for the secondary (or reducing resolution/FPS target) would solve it.
SLI/NVLink Not Applicable: Since these are different generations, you cannot use NVLink/SLI bridge (and NVIDIA has dropped SLI support for most Ampere cards anyway). All communication is through the PCIe bus. That means higher latency and lower bandwidth than a theoretical NVLink. It’s fine for this purpose, but it’s one reason we can’t get too crazy with frame multipliers. (Interestingly, some have mused whether using two identical Ada Lovelace cards with NVLink – if it existed – could supercharge frame gen, but that’s academic since NVIDIA doesn’t allow NVLink on 40-series except 4090 which has it disabled in drivers for SLI.)
Inconsistent Driver Support Beyond 2024: NVIDIA’s driver support for GTX 10-series is legacy at this point. By 2025, they may not be getting many performance optimizations. However, as long as you have a working driver, it should continue to function. If NVIDIA ever stopped supporting the 1080 in the main driver, you’d have to use an older driver (which could conflict if the 3070 needs a newer one). This is a potential future limitation – as of now, though, it’s working since the 537.xx drivers.
Power and Heat: Running a GTX 1080 at high utilization (especially if uncapped, trying to generate as many frames as possible) will make it run hot and possibly loud. That’s not a technical limitation, but something to consider. You may need to adjust fan curves or, as mentioned, undervolt it to keep it in check. The Ampere+Pascal combo will also dump a lot of heat into your case. Ensure your case cooling is up to par; otherwise, you might see thermal throttling which can undermine performance on either GPU.
No Frame Generation of UI/HUD elements specifically: One minor “limitation” of any frame interpolation tech, including LSFG, is that it has to treat the entire frame as image data. This can sometimes create artifacts for UI or HUD elements (for example, if a health bar or subtitle moves between frames, interpolation might blur it slightly). Engine-native FG sometimes can exclude UI or apply special rules. LSFG cannot differentiate – it’s essentially like an external motion interpolation (think along the lines of how TVs interpolate sports footage). It’s generally fine and not a major complaint from users, but just note that any on-screen elements that move quickly or animate oddly might have minor interpolation quirks.
Frame Pacing and V-Sync quirks: Some users have noted that getting perfectly smooth frame pacing can require some tweaking. For example, if the game’s output is not perfectly locked, LS might produce frames unevenly (especially before version 2.6 which improved this by tying to game’s framerate (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Beyond3D Forum)). The DXGI capture in current versions largely solved old pacing issues, but if you do see micro-stutters, it could be from the interaction of the two GPUs and the Windows DWM. Running in borderless means you’re at the mercy of DWM compositing; this is usually fine (and necessary), but it also means if something else on your system causes a spike (even an overlay or notification), it could affect the smooth output. In our Ampere+Pascal scenario, make sure unnecessary programs are closed to give maximum breathing room. It might also be wise to run Lossless Scaling itself in “Above Normal” priority (via Task Manager) so that it isn’t starved of CPU if your game is very CPU heavy. Likewise, having a strong CPU helps since it must orchestrate the frame copy between GPUs.
Ampere vs Pascal Feature Differences: Aside from optical flow, Ampere and Pascal differ in features like variable rate shading, etc., but those don’t directly impact LSFG. One thing: Ampere supports Resizable BAR (and if your platform and the game support it, it can marginally improve performance by letting the CPU access GPU memory more freely). With two GPUs, ReBAR is a non-factor for LS’s inter-GPU copy (that goes via system memory anyway). But if your 3070 has ReBAR enabled, just ensure it doesn’t conflict with anything with the 1080 (the 1080 will simply ignore ReBAR as it doesn’t support it). No action needed; just something to note if troubleshooting (i.e., you wouldn’t disable ReBAR just because you added a 1080, since it doesn’t affect it).
No multi-frame enhancement of input: As discussed, the limitation remains that only the rendered frames contain new game engine updates. So if your 3070 can only do 50 FPS in a game, even if LSFG outputs 100 FPS, your effective input sample rate and simulation rate is still 50 Hz. This is the same limitation as DLSS FG. As a result, very low base FPS (below ~30) are not very suitable – the interpolation might make it look a bit smoother, but you’ll feel sluggish input and large jumps in motion that are hard to interpolate perfectly. The LS developer recommends at least ~30 FPS base for 1080p, and generally the higher base, the better the final result (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide ...). So frame generation is not a magic fix for an underpowered system – you need a reasonable baseline performance to get a good outcome. In other words, the 3070 should still be able to produce a playable framerate; the 1080 then makes it even better. If the 3070 was struggling at, say, 20 FPS, LSFG might not save the day (it could try to make 40 FPS output, but the experience would still be sub-par).
Despite the above list, most limitations can be mitigated with proper settings. The Ampere+Pascal duo is actually one of the more common combos used by enthusiasts for LSFG (others pair Ampere with a cheap AMD card, etc., but using an existing GTX 1080 you might have is very sensible). Many have reported it works great as long as expectations are managed (e.g., use it for doubling to ~60-120 FPS, not expecting miracles like 30→240 FPS). Also, note that HDR output currently has a bit of a performance hit – running in HDR was noted to reduce LSFG performance by ~20% vs SDR (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). So if you’re on the edge of performance, consider playing in SDR when using LSFG for that extra headroom.
Real-World Benchmarks & User Feedback
Real-world testing from both individuals and tech outlets reinforces the viability of this dual-GPU frame generation approach:
Tom’s Hardware experiment: One write-up highlights how a GTX 1050 Ti (secondary) could be used with a stronger primary GPU to achieve frame generation at 1080p without impacting the primary’s performance. It emphasized that as long as the secondary GPU is “powerful enough,” you can get universal frame-gen with no performance overhead on the main GPU (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware) (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware). They do caution that at higher resolutions (1440p+), you “need more potent secondary GPUs” for the task (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware). In our case, a GTX 1080 is considerably more powerful than a 1050 Ti, so it stands to reason it can handle at least 1440p, and possibly 4K at more modest framerates.
User benchmarks: The community has created a crowdsourced spreadsheet of dual-GPU LSFG performance results (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Some interesting data points from users:
A user with RTX 3060 (12GB) + RX 5700 XT reported that the RX 5700 XT as FG card could comfortably double 1440p from ~60 → 120 FPS (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). This is relevant because an RX 5700 XT is similar or slightly stronger than a GTX 1080. It suggests that a GTX 1080 should be in the ballpark for doubling 60 to 120 at 1440p in many games (especially if using “Performance” mode FG).
An RX 5600 XT (a bit weaker than GTX 1080) was observed to top out around ~82 FPS → 164 FPS at 1440p (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). The GTX 1080 might extend that a bit further, but if targeting beyond ~165 FPS at 1440p, you might be hitting the card’s limits.
Conversely, at 1080p resolution, even a modest secondary like GTX 1050 Ti could reach ~180 FPS with frame-gen in performance mode (given a high base FPS) (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). A GTX 1080 at 1080p could likely do frame-gen well past 200 FPS if ever needed (though most monitors top out 144Hz, 165Hz, etc.). Essentially, the lower the resolution, the easier it is on the FG GPU, so you can either use higher multipliers or just know that at 1080p the 1080 will not be the bottleneck in most cases (the 3070 likely will max out first).
GTX 1660 Super vs RX 6400 example: Users found an RX 6400 (a very cheap RDNA2 card) outperformed a GTX 1660 Super in LSFG despite the 1660S being the stronger gaming card (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). This underscores that architecture matters – NVIDIA’s 16-series and Pascal cards rely on slower FP16/INT execution for AI tasks, whereas RDNA2 cards have double-rate FP16. So an RX 6400 could handle, say, 1440p 165Hz in performance mode (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!), which a 1660 Super struggled with. The GTX 1080 will behave somewhat like that 1660S/1070 class in terms of frame-gen speed. It will work, but an equivalently powerful AMD card might edge it out. If you ever find the 1080 lacking, one could hypothetically swap in an AMD card (like a used 6600 XT) as the FG card for better results. But again, with proper tuning the 1080 should be fine.
Subjective feedback: Many users describe the dual-GPU LSFG experience as transformative for certain games – “an absolute game changer”, “got neglected for far too long, now I see DLSS 4 multi-frame and I’m not impressed” (implying they already can do something similar with LSFG) (Lossless Scaling Major Update! (LSFG 3.0, New UI, Dual-GPU Usage)). The consensus is that for games where you want extra smoothness and your GPU can’t quite deliver it alone, this technique really delivers on its promise. People have successfully breathed new life into older GPUs or laptops by using the iGPU + dGPU combo in a similar way. As one Beyond3D forum user noted, “internally you are still running the game at the original framerate – so you aren’t breaking the game logic – but the extra smoothness certainly helps and makes those games more enjoyable” (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Page 7 | Beyond3D Forum). This highlights that unlike hacks that speed up game logic, this keeps the game’s timing intact, simply enhancing the output.
Use Cases: High-refresh gaming on single-player titles, playing games on high resolution without upgrading GPU, or even VRR low-framerate compensation (some have tried using LSFG to stay within G-Sync ranges). Another interesting use case: if you have a 120Hz or 144Hz monitor and a game that sticks around 40-60 FPS on your 3070, LSFG can make it look and feel much closer to true high-refresh output. The feeling of 100+ FPS with the stability of a lower true FPS is a bit of the “best of both worlds” (except for competitive scenarios as noted).
Potential issues encountered: Aside from the configuration hurdles (which we covered), a few people have run into things like black screen on capture (fixed by ensuring correct GPU selection), or LS app not starting the FG (usually fixed by running Steam as admin or similar, if overlay hooking is blocked). It’s generally stable software. If both GPUs are NVIDIA, one minor quirk could be driver overhead when both are under load – you might see slightly higher CPU usage from Nvidia’s driver managing two active GPUs. It’s usually negligible, but on older CPUs it’s something to consider (i.e., dual GPU might consume a few more CPU cycles). Additionally, if you record or stream gameplay, note that the secondary GPU doing LSFG is also the one sending the image to display – capturing from it is fine (you can use OBS on that GPU or on the CPU). But if you were used to using NVENC on your 3070 to stream, keep in mind the 3070 is now headless for display. You can still use NVENC on the 3070 to encode the game frames (since it’s rendering them), but you’d have to do a bit of manual setup in OBS to pick the right GPU for capture and encoding. It’s not a big problem, just a consideration if streaming.
In summary, real-world benchmarks show strong results when using an RTX 3070 paired with a GTX 1080 for LS frame generation, provided the system is configured properly. Users have achieved substantially higher frame rates and smoother gameplay in GPU-heavy titles like Cyberpunk 2077, and even upcoming titles like PoE2 are seeing benefits. The trade-offs (slight latency addition, configuration complexity) are generally seen as worth it for the gains in fluidity. It effectively extends the life of your Ampere GPU by giving you a feature (frame interpolation) that NVIDIA otherwise reserves for Ada Lovelace GPUs only. As one early adopter put it: “Dual GPU LSFG is a lifestyle.” – it requires some tinkering, but once set up, it’s hard to go back! (Dual GPU LSFG is a lifestyle. : r/losslessscaling - Reddit)
Key Recommendations and Best Practices for Dual-GPU LS Frame Generation
To conclude, here are the bullet-pointed recommendations and best practices for using Lossless Scaling’s frame generation on a dual-GPU setup (RTX 3070 + GTX 1080):
Use an Adequate Secondary GPU and PCIe Slot: Ensure your secondary GPU is powerful enough for your target resolution/FPS. A GTX 1080 is generally capable for 1080p and 1440p frame generation, and can handle 4K at lower FPS. Make sure it’s installed in at least a PCIe 3.0 x4 slot (or better) – bandwidth is critical for smooth frame delivery (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). For 4K gaming, PCIe 4.0 (or x8 3.0) for the secondary GPU is recommended to avoid bus bottlenecks (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!).
Connect the Monitor to the Secondary (FrameGen) GPU: Always plug your display into the GPU doing the frame generation (GTX 1080 in this case). This avoids sending the processed frames back over PCIe, which would introduce major latency and performance issues (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). The render GPU (RTX 3070) will forward frames to the 1080 which outputs them directly to the screen.
Configure Windows to Use the Correct GPUs: In Windows Graphics Settings, designate the RTX 3070 as the High Performance GPU (for rendering) and the GTX 1080 as the Power Saving GPU. On Windows 11, set the system default or per-app setting for your game to use the 3070 (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). On Windows 10, use the registry hack to force the 3070 as “HighPerfAdapter” if needed (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Also set the Lossless Scaling app itself to run on the 1080 (so it captures on the GPU connected to display) (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Beyond3D Forum). This ensures the game runs on the fast GPU, and LSFG runs on the secondary.
Limit the Game’s Framerate for Stability: Cap your in-game or driver FPS to a level that the secondary GPU can reliably double (or whatever FG multiplier you use). For example, if you have a 144 Hz monitor, start by capping the game at 72 FPS to target 144 FPS output. Using in-game limiters or Rivatuner is recommended to achieve a steady base frame rate (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]) (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). A stable base frame rate results in smoother frame pacing when generating frames. Avoid running uncapped, as that can overload the secondary GPU or cause uneven pacing.
Optimize LS Settings (Quality vs Performance): In Lossless Scaling, choose a frame generation mode suitable for your GPU power. Quality mode yields better image quality but is slower to compute; Performance mode trades some quality for speed and may allow higher FPS on the GTX 1080 (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). If you find the 1080 is maxing out, try switching to Performance mode FG. Also decide between Fixed FG (constant 2×, 3×, etc.) and Adaptive FG (which tries to insert frames based on need). Many users prefer fixed 2× for consistency and lower latency, as adaptive can introduce variability (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). You can experiment with higher multipliers (3×, 4×) if your secondary GPU has headroom, but monitor the actual results for frame pacing issues.
Use Appropriate Resolution/Upscaling Settings: If the RTX 3070 struggles at native resolution, don’t hesitate to use LS’s upscaling features in tandem. For example, render at 1080p or 1440p, let LS upscale to 1440p or 4K using FSR or integer scaling, and enable frame-gen. The visual hit is often minor with a good scaler, and it reduces load on both GPUs. However, note that enabling an upscaler in LS will also consume some GPU resources on the secondary card. A balance must be struck – alternatively, use the game’s own resolution scale or DLSS on the 3070 to lighten its load, and let LS only do frame-gen. Do not use LS’s scaling if the game is already at your display resolution and you only want frame-gen – in that case set Scaling Type to “Off” so it just passes through.
Watch Temperatures and Power: Both GPUs will be working; ensure your PSU is up to the task and temperatures are in safe ranges (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). It’s often helpful to undervolt the secondary GPU (GTX 1080) because running it at 100% for long sessions can draw a lot of power and generate heat. Undervolting can reduce temps and power by 10-20% while maintaining near the same performance for AI frame generation (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Similarly, make sure the 3070 isn’t throttling due to the reduced PCIe lanes (if any). Generally x8 vs x16 has minimal impact (<5%), but keep the 3070 cool to boost its baseline FPS.
Disable Conflicting Sync/Buffering Options: For best results, use borderless window mode and let LS handle V-sync if needed. Disable in-game V-sync to prevent it from capping the FPS (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]). If you get tearing, you can enable LS’s v-sync or use driver-level Fast Sync/Enhanced Sync. The goal is to allow the game to run at the uncapped (or capped to half refresh) rate and let LS insert frames freely. Also, set the game’s “max pre-rendered frames” or similar to 1 if you can (low-lag settings), to minimize baseline latency. Some games might require tweaks (as one guide noted for Far Cry titles, adjusting the GPU buffered frames helped smoothness with FG (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025])).
Address PCIe Bottlenecks if Observed: If you notice that both GPUs run high utilization yet performance is worse, you might be hitting a PCIe bandwidth limit or overhead. In such case, check your motherboard’s PCIe config (e.g., ensure secondary slot is running at its max lanes). You can try moving the secondary GPU to a different slot (some boards have a third slot that might be x4 from chipset; sometimes that can be better or worse depending on if the primary then stays x16). For instance, one user found that using a lower slot that was PCIe 2.0 x4 was too slow, so they stuck with the x8/x8 setup (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions) (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions). If you only have PCIe 3.0, x8 for secondary is ideal; x4 will work but at 4K it may cap performance. Also, disable any power-saving states for that slot as mentioned (Link State PM). Essentially, ensure the full bandwidth is available and utilized. Tools like GPU-Z can check the active PCIe mode (while running LSFG to see if it downclocks).
Keep Software Updated: Use the latest Lossless Scaling version, as the developer frequently improves performance and fixes bugs (e.g., the move to DXGI capture in v2.6 greatly helped performance (Lossless Scaling. FGx2-x20 & upscaling on ANY GPU! Miniguide page 11 | Beyond3D Forum)). Likewise, keep your GPU drivers updated for best compatibility. Join the Lossless Scaling Discord or forums for up-to-date tips; for example, if a particular game has an issue, the community often finds a workaround or the dev patches it.
Mind the Limitations: Remember that generated frames do not improve input lag or game mechanics. Avoid using frame generation in competitive eSports-style games where latency and absolute precision are critical – it’s best suited for single-player or cooperative titles where fluid visuals enhance the experience. Also, if your base framerate is extremely low (<30 FPS), focus on improving that (via graphics settings or upscaling) before layering frame-gen. Frame generation works best as the last step once you have a playable base framerate. Finally, manage your expectations for the GTX 1080 – if aiming for very high resolutions or triple-digit FPS, monitor its usage. It has a finite “frame output” limit as observed by users (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!). Adjust the target (either lower resolution or lower the FG multiplier) to stay within what the card can handle for consistent results.
By following these recommendations, you can maximize the efficiency and benefit of a dual-GPU setup using an RTX 3070 and GTX 1080 for Lossless Scaling frame generation. This configuration can significantly extend the capabilities of your system, allowing you to enjoy modern games with higher frame rates and smoother visuals, approaching next-gen GPU features without the immediate cost of an upgrade (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware) (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware). The end result is a uniquely powerful setup that leverages both GPUs to their strengths – truly getting the most out of your hardware for gaming and AI-assisted frame generation.
Sources: Real-world user guides and benchmarks for Lossless Scaling FG (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!) (Steam Community :: Guide :: Dual-GPU Setup For Even More FPS With LSFG!), Tom’s Hardware overview of dual-GPU frame-gen (Offloading Lossless Scaling Frame-Gen to secondary GPU eliminates overhead | Tom's Hardware), and community experiences on frame generation performance and configuration (Dual 4080-S GTX-1080 performance :: Lossless Scaling General Discussions) (Steam Community :: Guide :: List of games that work well with Frame Generation [Updated April 2025]), among others, as cited in the text above.