Upgrading from a 7900GTX SLI

yes u will notice a difference. The 4870 will perform much better then ur to old 7900gtx in sli. ur fps will probably double! =]

wow... thats incredible! Only had these 2 cards fo 1 1/2 years and technology has advanced quite a bit lol... think I spent £600 those days for these babies... now worth £100 for the pair   Thanks for the reply  

BTW, I heard these 4870 in Xfire will need quite a bit of power, I have the OCZ 750W PSU... would that be OK if I decided to buy 2? - Although from the sound of it, performance wise might be daft. I usually game @ 1600 x 1050

yea tech changes constantly, watch when u buy the 2 4870 they'll be outdated within a few months tech adv soo fast.
Dont worry about ur psu its more then enough to handle 2 of those in crossfire.
(im hoping u have a new mobo and not using the same mobo with ur 7900gtx sli. thats a sli board 2 4870 wont work on that u need a crossfire board.)

If you keep your board get the GTX260, neglible performance difference. and you maintain SLI potential.

I am acutally using a P5W DH - i am using hacked drivers for XP to get it to run in SLI. Of course in Vista, it will only be using 1 card as this board is 'only' supports Xfire  

arent u slick lol.
so ya ur ready for the 4870! if u pick it up let us no how smooth it feels.
good luck.
=]