Im looking at two cards for my new build the ATI HD 2600xt 256mb GDDR4($118) and the NVIDIA BFG 8600GT 256mb GDDR3($150) wich one has the better perfomance in both DX9 and DX10 and would it be worth having two of them, or just one ATI HD3870 512mb GDDR4 ($250) and thanks for the info.

I'd just go with a single HD3870. Less headaches than running CF or SLi.

If you're willing to spend $250.. I would tend to say get an 8800GT for a little bit more if you can. Otherwise I'd go with the HD3850 as well.

Ok thanks the last question I have is between the two mentioned cards the HD2600xt256GDDR4 and the BFG8600gt256GDDR3 as a single card wich one would be the better of the two for gaming performance?

What kind of games are you planning to play? I'm not trying to be brash but you don't buy the 2600XT/8600GT because you want to play the best games at a good resolution. HD3850 or 8800GT is the bare minimum to play games from 2008.

Ok a finaly choice then the HD3870 512MB GDDR4 775/2250($247) or the 8800GT 512MB GDDR3 600/1800($278) I will be playing Crysis, COD4, NFSPRO, DIRT, on this system.

The GT is benching between 10 & 20% better results than the 3870, hence the price difference you listed is on par.

I've got a 3870 on order with the hopes that newer bios versions will close the performance gap.