Oh and BTW, I would recommend OverClocking your GPU & CPU which would make your rendering lower by few hours but better watch those temps on GPU and CPU, dont hit anywhere near 75*C but 70*C is fine... For your OS, I suggest getting the Ultimate version! It's more compatible with a lot more stuff than home premium!!!
Just download from those download site but you use at your own risk, i downloaded over hundreds of downloads from download site and it made me happy having windows 7 ultimate 64-bit for free XD... But it's at your own risk due to Virus!!!