Thanks Cayars and FortuneNVirtue,

Seems you guys agreed on the problem. I will do as advised. Will start by leaning down through BIOS see how that goes. Then will go on and purchase a better CPU. Any CPU in particular you recommend?

I've also tried running nvminer on only 1 card with the -d option as recommended but I get the same hashrate as before. No improvement.

Here goes the screenshots anyways for the posterity:

http://valid.x86.fr/y1vta2