Can my system handle a GTX 780?


Yeah but is my PSU cheap and can it stand those two in one case?
 
I would not put two GTX 780s with anything below 750w myself. Some would say 850w. there are a few sites that use PSU calculator. Coolermaster does and there ara others. I will link if you don't already know about them. The FX 8320 once overlcoked can use quite a bit of power and get hot. Depending on the frequency and voltage of course. SeaSonic S12II 620w is a solid PSU. good value.