For a practical demonstration of what denoising can theoretically do I recommend Quake II RTX. There is a dev mode with a bunch of rendering settings, many more

For a practical demonstration of what denoising can theoretically do I recommend Quake II RTX. There is a dev mode with a bunch of rendering settings, many more so than in an average game. They were added to it because this game is more of a tech demo of RTX at this point. There is a switch where you can turn the denoising of the ray-traced output on/off: it shows tremendous difference, to a point where it's hard to even imagine looking at the noisy image that it is even possible to extract the denoised version.