Guru3D compared the Windows 7 (Final) vs. Windows Vista VGA game performance. Here's a taster:

Windows 7 is a very promising platform for many reasons. For me personally, Windows 7 is what Vista was supposed to be really. With our pretty spiffy test platform we can tell you that it's a pleasure of an operating system to work with. It's fast, good looking, diverse and most of all... very stable on all levels. Neither with the NVIDIA or ATI graphics cards did we run into any issues, and that is quite remarkable considering we are at the threshold of a new operating system era.

The VGA drivers are not only stable, they work really well and perform good as well. I was afraid that with the coming of a new OS we'd see a performance drop just like we had with the transition from Windows XP to Vista, but if anything, Windows 7 VGA performance is as good as Windows Vista with the obviously occasional random fluctuation in performance here and there though. Looking at the opposite side, Windows 7 won't offer performance increases in graphics performance either with an exception here and there.

Windows 7 will obviously bring a lot of good stuff along with it in the near future... though it will be available for Vista as well, DirectX 11 is just around the corner. Better shaders, better shader performance, a new compute shader and hardware tessellation are just some of the few new but exciting items that DX11 will bring. Of course this website can't wait until some actual DirectX 11 class graphics cards are released ... and along with it software applications and games.

So if you are a little afraid of picking up Windows 7 due to driver issues... don't be. It's stable and working really really nicely. Two big thumbs up to both ATI, NVIDIA and sure .. Microsoft. And as a testament to that, let me assure you, we'll be switching all our test systems towards a Windows 7 based platform... real soon.