What? You're running a 2pin to your 4pin CPU? :O I'm surprised it even boot. haha Use the 4pin from your PSU, it's hard to miss because there'e only one with like that. I doubt you PSU have a power pin for a PCIe. We have the same specs, I'm running crysis 3 smoothly, sc2 HOTS, AC3.
Another thing, are you running your mems on dual channel? That would be a big help!
The PSU only had a 4pin end connector + 24pin? connector so i connected both on my motherboard which
only had 8 pin socket + 24 socket .
24pin one was put correctly but i am not sure of the 4pin one.. I researched it and it says that its okay to put it in
like that but i guess.. the power might be the problem..
ah... anyway.. i ordered corsair 430W and another radeon HD 7750..
i was so mad lol..
anyways. thank you for your answer!!