I have a 790x chipset gigabyte board. It is capable of taking a 1090T or 1100T. However those CPUs are running around 170-180 used. I have been looking at the old Core I7 920s which were four core with hyperthreading. Mobo/CPU combos run around 250-270. All the new I7 systems are up there in price range. 300 bucks just for the cpu usually and another 100-150 for mobo. Would the I5s be a worth while upgrade at all? I've read the piledrivers aren't that good for crunching due to being integer driven instead of floating point. Not even sure a new CPU would give more of a bump for the cost. GPU seems to be where it is at. Might be worth buying a 2nd 580GTX and new PSU.