i know that the "6800 ultra" was made for doom 3 and that the X800 beat it
Yeah you got that backwards, 6800 owned the ATI card in those trials. The 6800GT is your best bet...like beedub said, an eVGA brand 6800GT card.....like he also said...they put the same heavy duty heatsinks on ALL their cards I believe...even the 128mb so you are assured good cooling...technically better than stock if you think that the heatsink used for the ultra is also being used on their GT. it's mainly ATI fans who will route for ATI (waiting for ag3 to appear) but in all truth, Nvidia has taken the cake with their new card. And the soon to be released 6600 series (mainstrem model of 6800) will also outperform the ATI Equivelant. I think they just rushed their card out too quick to try and compete, but I think in the next gen cards, the:
eVGA 6800GT 256mb Card is your best bet.
for more information, don't buy through the site though cause you can get a better price at zipzoomfly.com obviously. Maybe the top top top of the line X800's do aright, but for the most part I think their new cards are somewhat buggy and won't perform as good or as stable as the 6800. I still would have to agree on just overclocking the GT to Ultra speeds because the Ultra is a monster and will probably get pretty hot, not to mention they recommend ATLEAST a 480w power supply and thats assuming it's a good brand. So you'd probably want a 560w you can get one from thermaltake for $100
If the 6800 Ultra drew everything that it was supposed to, then the X800 XT PE would cut it up
Can't help it that ATI wasn't smart enough to think of the 'dont render black' option
Makes a lot of sense really and seems to really help too