Originally posted by: cputeq
I went over this same debate for about a week straight, reading review after review and benchmark after benchmark. Here are my conclusions, and why:::
Out of the 8800-320 -640 or the 2900XT, I went with the -640.
1) I have a 19" monitor and want to play some games at 1920x1200. The 640 was the safer bet over the 320.
2) ATI seemed to have driver problems with several games (especially OpenGL-based) in multiple benchmarks. Nothing unplayable, but slower than normal. Of course, there have been driver revisions since then, but I still kept that in mind. It typically seems ATI has more overall driver problems than Nvidia, but makes great improvements for each driver release...still, I felt a bit uneasy with the drivers (not like Nvidia is much better though)
3) The 640MB card just seemed more "future proof" than the 320MB card. Some benchmarks had the 320 either slowing way down or not even able to run the game at a given resolution and/or AA level. Also, the 640 generally performs better using AA modes.
4) The ATI card took up way too much power. I feel even if the newer card appears, and it's based from the same core, it's going to suck a lot of power. With my 640, I'm able to run it from my Zalman 460W (just barely) because it only uses 1x PCIe plug.
Overall it was pretty easy for me. I was really leaning for the 320MB because of cost, but decided to blow the ~$75 more for the 640MB. I was strongly considering the ATI card, but driver worries (small problem) and power requirements (big problem) prevented me from buying that card.
Also, I happened to get an EVGA card, which comes with a lifetime warranty and has a step-up program. That was also a deciding factor.
If I would have had a sufficient power supply to run the 2900XT, the choice would have been much harder.