I'm running Windows 8 RC, downloaded the ISO about a week ago. I've seen varying results for games when it comes to Windows 8. My only personal source of reference for graphics is Minecraft, in which performance is more than halved. At the same time, apparently FarCry 2 sees a significant drop as well (on a different machine), so I don't know what would specifically cause it. For my laptop, I'm using a MacBook Pro with both Intel Integrated and and NVIDIA card. No new drivers have been released by Apple specifically for Windows 8, so for now I'm just using the Windows 7 drivers. Therefore, I'm not exactly the most reliable source for benchmarking.