card comparaison need a fast reply if possible please

firstly i apologize for the rush but i don't have long to get to the bottom of this

a little background

i bought a xfx geforce 7800GTX 512 XXX limeted edition PCI-E for £540 and after a few months it broke i sent it back 2 and a half months ago and now they are sending me a EVGA GeForce 7950 GT 512MB GDDR3 HDTV/Dual DVI (PCI-Express which only costs £223 from what i can find out myself it has lower clock speeds and lower MHz and a much lower price (which there was no mention of paying me the difference) i am looking for benchmark results but i am not having much luck so I'm hoping somebody here can tell me how these cards compare to each other and if performs as good or better than my old 7800gtx 512 xxx

thank you all in advance