hey all. back again heres the question, im into cod2 online, I dled the cod4 demo my vid card wont play it

. ok new vid card time i dont want to have to buy another card for quite awhile so i might as well throw down some $ for a good 1, i want to get a nvidia 8800gts with 640mb of memory on it, i have seen that theres a few different types of that kind of card i am gonna do the buy from e-bay thing and i hope i have about $250. 1st i have a p4 titan mobo with a intel Lga775 processor, a okia 450atx power supply, im also getting a 1gig dual core stick of ram, (something like that anyway) knowing what im working with now will what i have work with that vid card? oh 1 more question i seen that theres a nvidia 8800 gts a nvidia geforce 8800gts a evga 8800 gts, i really am confused by that can, you maybe help me understand the differences not all the specs and technical what not are they basically the same cards or what? and its to play the new cod4 also. thxs i appreciate any and all helpfull insight with this.