who says you cannot overclock a non k series i5 cpu ? you can but the overclocks achieved wont be as good as a k series cpu.
if you are playing at 1080p dont get 2 7950's .
a single 7950 will max out any game with 60+ fps at 1080p.
You can overclock by using the BLCK and ruining the rest of your computer if you want more than about 200MHz, sure...
Also, for whatever reason he wants over 100FPS. I don't know why, but SLI/Xfire is what'll get him there.