Benchmarks from QuasarZone show that a near tripling in performance can be achieved in some games by using both DLSS Frame Generation combined with AMD's Fluid Motion Frames. This is possible thanks to a multi-GPU solution that allows an Nvidia 40-series GPU to render using DLSS Frame Generation and then have an AMD GPU to take that output and generate even more frames via Fluid Motion Frames. So pairing two of the best graphics cards for maximum faked frames is possible. Practical? That's a different story, and there are quite a few caveats to this dual Nvidia-AMD setup that makes it unlikely to be useful in practice.
How QuasarZone got this working is a little tedious. It installed both an RTX 4090 and an RX 6600 into its test system, installed drivers for both, and then had the primary display hooked into the 6600. Then in Windows, it selected the 4090 as the rendering GPU, which allowed the 4090's DLSS 3 Frame Generation content to pass through the 6600, which could then allow AFMF (AMD Fluid Motion Frames) to generate even more frames.
In Cyberpunk 2077 and Starfield, the performance boost with both DLSS 3 and AFMF enabled was nearly 3X. Starfield's results were achieved even without DLSS Frame Generation, which isn't supported in the game. Call of Duty: Modern Warfare III and Ratchet & Clank: Rift Apart saw roughly a doubling in performance. It certainly sounds impressive on a surface level. However, this solution isn't exactly without problems.
First, it requires having two GPUs, one from Nvidia and one from AMD. Thankfully, even an RX 6600 is sufficient for the AFMF aspect, but that's still an extra $180, more space taken up, and more heat being generated.
More critically, the performance claims require a bit of an asterisk. Although combining DLSS and AFMF resulted in a big increase to the average framerate, the 1% low framerate either didn't budge much or went slightly down. Ideally, the 1% low framerate or 99th percentile framerate will be as close to the average FPS as possible. Increasing the average FPS while decreasing the 1% low FPS could result in a choppier and less smooth experience.
Finally, there's ample opportunity for visual quality to take a big hit. QuasarZone didn't show any screenshots or videos in its testing, but just thinking logically about what's going on gives plenty of cause for concern. We know that both frame generation technologies don't leave visuals 100% intact, and combining two of them seems like a recipe for disaster. Plus, user input latency should be atrocious. The 4090 would sample user input once for every two frames, and then AFMF would try to double down on that, meaning one input sample would be used for every four frames that get sent to the display.
For all of these reasons, it's very unlikely we'll see gamers picking up two GPUs to see a potentially big boost in performance. It's almost like CrossFire and SLI, which were also multi-GPU technologies that didn't exactly work well. Of course, CrossFire and SLI at least were officially supported; combining DLSS and AFMF isn't and almost certainly never will be.
