Windows 8 isn't supported, so expect many issues with software that wasn't made for it.
^ This. Also, various drivers such as for your GPU may not necessarily support Windows 8 beyond the minimal basics. IE, you can get your desktop (or in Windows 8's case Metro

), but the GPU won't function right when it comes to more complicated stuff like gaming.
I don't think it's ever been recommended that you use an RC candidate OS for anything other than basic testing and trial use. Most definitely not for complex programs like a game. My suggestion is that if you want to do any gaming, you downgrade back to Windows 7 and wait to upgrade to Windows 8 when it has a proper release.