I've come across a minor concern in my trial of Windows 8. In particular, I have noticed some rather disappointing graphics issues with my two-year-old notebook's ATI Radeon HD 4570 chip.
At the right, you can see an image of the Games for Windows Live application Game Room. The only really odd thing about it is the fact that the avatar is a rather generic one, rather than my actual avatar (which the Xbox version of the game uses).
To the right, here, is the same application, running on the same hardware, booted from a Windows 8 partition. The same generic avatar appears here, but with obvious rendering issues. The issues occur also in the "arcade" virtual world, making the arcade impossible to navigate or use (large triangles would block out most of the viewing area).
This picture is of the recent game Microsoft Flight on the same Windows 8 partition. In addition to the wide zebra stripes in the skybox, there are rendering issues with one of the planes that comes free with the game (some invisible triangles, some other triangles that stretch through the cockpit). Oddly enough, the other plane doesn't seem to have that issue. (I would have a picture from Windows 7 picture for comparison, but it won't run on my Windows 7 setup for some reason — it may be time to rebuild the thing.)
I did some internet searching, and there were some suggestions about going to the video card manufacturers' websites to find updated Windows 8 drivers. I checked the AMD website for drivers for my notebook's ATI Radeon Mobility HD 4570. There were Windows 8 Preview drivers for the HD Radeon 5000 series and newer, but nothing for the 4000 series. Some of the websites I found earlier suggested downloading the Windows 7 drivers, just like Windows Vista drivers would work on Windows 7. However, AMD's download site didn't provide direct links to the drivers, just an automated installer application, which refused to install any drivers on my "undetected operating system".
Now, this is just a preview, so it is very possible that, by the time Windows 8 is released, drivers will be available for all of the ATI chips, or that the included drivers will be fully functional. It is just making it rather difficult to make a truly objective assessment of Windows 8 when the only video driver I can use has such obvious issues.