Good choice on the powersupply, it'll handle an overclocked HD7950 easily, even with an overclocked CPU.
If you're going to overclock you'll need something like the Gigabyte card, the Powercolor card has a reference cooler, which is fine for normal uses but will quickly become both hot and noisy when the card is pushed.
One, overclocking has no warranty, some cards do well, others are poor overclockers, so do n't set your hopes too high.
Two, cards like the Gigabyte dump all their heat into the case, it is importaint your case is well ventilated for the cooler to work well.
it has room for fans on top and a built in fan in the front so maybe that will be enough ventilation? I mainly want it cuz its pretty and cheaper than the haf 922.
also, I just want to OC the 7950 because it looks like everyone else with that same card does. also, 800 mhz seems a tad low, especially since ATi bragging about how the 7xxx series comes with 1ghz at stock. does it really matter if i squeeze out an extra 100mhz?
thanks for the quick answer.