Alright got around to trying it today in XP Pro SP2. I hooked up the V2 to a second monitor just to be sure it was actually engaging when it needed to (advantage of having two monitors to test with). Anyways, tried two different unofficial drivers from 3dfxzone.it - FastVoodoo XP 4.0 and LegendgrafiX 2.0. The short story is: it doesn't work, and the card is coming out, and Windows is being re-installed.
The long version is: both install very nicely, neither created instability (which the release notes said could happen), there was no problem having them hooked up with the GeForce FX (and I had it on pass-through during installing Windows - no problems there). LegendgrafiX is in a language I don't speak (I can't even tell you what language it is) so that might've been part of the problem there, but it just never let the card enable. FastVoodoo XP 4.0 would have the card show up in CS, but anything higher than 512x*** and it would crash, and when it did render it had MASSIVE problems with lighting and texturing. Under 2k the card had no problems doing 640x480 or 800x600 - looked pretty indiscernible from the WildcatVP when I tested that out. At this point I'm kind of "done" with it, and I'm not spending anymore time screwing with it - the system is getting nuked and re-done with a clean XP install (the uninstallers on both of these drivers are a joke - both CTD with no error) and just going with the FX. The V2 is going to go back in either the W2k system, or a Win9x box.
On a more positive note, the 5900XT at stock with the new P4 scores a nudge under 17k in 3D01SE (16875 if I'm remembering right - I have screens but didn't take them off the machine); OC'd to 450MHz core it does about 500 pts higher. So the 5800U should be doing 17-17.5k (or better) based on how it compared to the XT on the 2.0GHz and the 450MHz results. That's almost 10k pts increase and pretty substantial increase in measured FPS in all of the tests - hopefully that translates to games as well (not that anything on the 2.0GHz is having problems, but faster is nice). And it's quieter thanks to the giant heatsink it came with. 😀
