Radeon 2900XT & GeForce 8800GTX

the answer to your question lies in the other specs for both cards. If you look at how they both work you will see, try using wikipedia to find out what ROP's texture units etc etc are.

hope this helps.

If you notice the pricing, the hd2900xt isn't in the same price bracket as the 8800gtx... it's $150 cheaper than the 8800gtx. It's a comptetitor to the 8800gts 640MB.

However the reason it's slower than the 8800gtx is mainly because previously released games make heavy use of texture mapping units (TMU's) and rastor operation processors (ROP's). The 8800gtx has 32 TMU's and 24 ROP's, while the hd 2900xt has 16 of each. The 8800gts has 20 TMU's and 20 ROP's. Also, the 8800 series has higher shader clocks.

However, general speculation and evidence suggests that newer games, particularly dx10 games, will be extremely shader heavy, which the hd 2900xt seems to excel at, if you look at shader heavy games released allready (STALKER.) Right now, the hd 2900xt's performance with current gen games seems to fall right between the 8800gts and 8800gtx.