Hi i have a QX6850 EXTREME overclocked in the bios from 3.0 ghz to 3.67 ghz and 8 gigs of ddr2 ram and an 860 sli motherboard and i dropped in a ASUS GeForce GTX 660 DirectCU II OC 2GB GDDR5 which totally improved my gaming ability, i play world of tanks and i had 2 gtx 8800 in sli mode and could only play in low mode in the standard graphic mode, now i can play in the improved mode with most of everything running at maximum, also our cpu,s are nearly the same so i think you will good to go, also i am sure that its not being bottlenecked by my cpu cos while i am gaming my gpu is running at 100%....i have just posted a question asking if i bought another gtx 660 and ran in sli mode would i see even more gains or would i be asking to much...