<< but the 9x/ME drivers will "bench" better due to the fact that Win2K and Nt base OS's just aren't optimized for full-on performance but for stability and application... >>
I have to disagree w/ that a bit. If you look at Nvidias drivers you can see that the perofmrnace is just about equal. Also, the NT kernel is far more efficient than is the 9x so actually if the dirvers are developed correctly, NT/2k should outbench a 9x anyday (why do you think the xbox will have a base NT kernel? (2k to be exact)).
about the v3 drivers... I had/have a v3 running on win2k for quite some time and the 2k drivers are fine (at least the were to me). Now I dont play q3a THAT much, but i do play and they worked fine. I dont have any comparison benches but if 15% loss is what you will be getting, in my opinion... id rather have the stability and efficiency (not to mention the security) of 2k and the 15% degradation, than have marginally faster performance and a 9x kernel. Thats just the way I see things though, so it depends.