Best Dollar value upgrade?

[Lonewolf2nv]

I currently have two Nvidia 7900GS in my system which is about 3 years old now. I recently have noticed several games that I am running into that are just too much for the cards. I upgrades to Windows 7 and put 8 gigs of ram in which has helped with some issues but I still think the video cards are the bottle neck. I have always been a fan of Nvidia cards but I am in no way against switching to ATI. I have been reading articles here and researching on NewEgg and Im torn between buying two HD5770 and running them crossfire for roughly $340, or spending quite a bit more and buying two GTX275 and running them SLI for roughlty $500. I guess I am just looking for some opinions, I just want the best bang for the buck. I do not mind spending the $500 if I am truly getting $160 more perormance wise. I appreciate any and all feedback on this.

 

[Lonewolf2nv]

Well my computer is a Dell XPS 710 , Intel core2 extreme processor x6800 (2.93 GHz, 1066 FSB) w/dual core technology and 4mb cache, 8 gigs of ram, two nividia 7900GS running SLI, dual WDC Raptor 160 GB 10,000 rpm raptor hard drives striped. I run a samsung 226bw wide screen monitor at 1680 x 1050. I contacted Dell and they said that my system could run the ATI crossfire setup (hopefully they know what they are talking about).

I was actually looking at just one card I guess in my mind I was thinking my computer is setup to use two video cards would'nt that be the better way to go but then again I am by far no expert on the matter. I do know that the size of the card is no real issue the case they use for the XPS is huge its almost 3' tall and deep and at least 14" wide.

 

[Lonewolf2nv]

Best answer selected by Lonewolf2nv.