What is the rest of your system? Please include the PSU make/model and if you know what the amps on the 12V rail are, so we can recommend you something. The 7600gt is a good card, so upgrading to a 8800gt will probably bottleneck your CPU. The good thing is that if you upgrade your CPU later, you can reap the benefits of that upgrade. You might need more memory, but don't know your system specs.
u've got socket 939(i had an old amd 64 3000+)
if u've got cash get these and you are good to go:
cpu--amd opteron dual core 175-@ 2.2ghz stock with 2 mb L2 cache
get an antec/corsair psu--550watts --600watts should do.
and then get the nvidia 8800gt 512mb.
or if you don't have a big budget and only need the gfx card get a nvidia 8600gt/8600gts--it won't bottleneck ur cpu and will run on ur existing psu
Probably, and you won't need to upgrade you PSU, so that would save you some $. I'd consider that to be your best option. The 2600xt is good too, but requires a little more power. With the driver updates that AMD has been doing the 2600xt has been getting a little faster. 8600gts makes good sense, especially if you don't spend too much on it. Ooops, forgot to mention I have a 3200+ w/x1800xt on it and it doesn't seem to be bottlenecked, so I believe.
if ur planning to play games on this a64 machine of urs-the recent games would be nothing more but slideshows--crysis wouldn't even run i guess.
but u can play old games or if u plan to use it as a HTPC then the ati radeon x2600 card would be great! its better than the 8600gt when it comes to video decoding and stuff. http://www.tomshardware.com/2007/10/26/avivo_hd_vs_pure...