AMD has very poor drivers for linux: their compliance with latest OpenGL standards is very late compared to nVidia proprietary drivers (already supporting OpenGL 4.5) and performance on higher end cards reaches a bottleneck in framerates for no clear reason while cheaper nVidia GPU outclass them. This being said, you have decent open source drivers for AMD cards, but they can't compete with nVidia on performance yet anyway.
Oh. Right. You better not talk about gaming anything on SteamOS with a AMD GPU onboard – that can only end with sore disappointment."
Is there an issue with amd gaming on linux? I though nvidia were the ones who wouldnt provide drivers?