How to use 2 different GPUs for Gaming

Overview:

• Lossless Scaling is a program that allows you to use up-scaling and frame generation even on GPUs that do not support it
• It works similar to FSR or DLSS
• Many people tried two different GPUs with Lossless Scaling with impressive results
• You may use whatever GPU combination you like: AMD + NVIDIA
• It only costs 6.99€ 
• This is not a guide on how to set up your gaming rig

How it works:

• Lossless Scaling gives you the option to chose which GPU will handle the game rendering and which will handle the frame generation
• You are able to choose the frame generation multiplier (x2,x3), so if you can run a game at 20 FPS on 4k and enable frame gen x3 you will get 60 fps
• Why two GPUS? You can use a single GPU to increase your FPS, but the generation stresses the GPU, so for a rough example: If you have a single GPU and run a game at 20 fps, the x2 upscaling will not result in 40 FPS sing the frame gen will stress the GPU more. It will result for example in 33 or less
• For optimal results, you have to use the more powerful GPU for rendering and the less powerful for the upscaling, since the rendering requires more power. For example: if you have an rx580 and a 5700XT GPU, you have the render the game with the 5700XT and upscale with the 580
• Using a very under-powered GPU as upscaler might result in worse performance, so for example don't use an NVIDIA 710
• It only works in borderless windows mode
  

Result:

• If you play games on 1080p 60fps and decide to use the upscaler to go for 4k gaming, the resolution will make a big difference in the image produced, sharper with more clarity. But the result is not always perfect, as when you increase the multiplier it can result in ghosting or input delay. 
• The input added is small and in single player games you will not be able to notice it as much.
• Of course it is not recommended for competitive gaming where the input delay can affect the result of a match
• The main point of the whole setup is to improve the gaming performance, and the most important of all: If you are not able to play a game due to its low framerate and you are able to thanks to the Lossless Scaling, while keeping your current GPU and not being forced to upgrade, is a win for me.
  

Verdict:

• If you have an older GPU laying around, and a high enough PSU that can handle both, definitely give it a try.
• I don't think buying a second GPU just to use this is worth it. If you want to buy a GPU definitely go for an upgrade.