does your mobo report psu voltage info to the os? try a program like speedfan or hwmonitor ect and see what the various power rails do under different loads. http://www.tomshardware.com/forum/290251-28-testing-stability I am indeed using speedfan, but i don't what the acceptable margin for voltage ...

I also came up with 445 - 450w with a PSU calculator. So i guess i can't expect to achieve quiet opration... Thanks a lot for the answers, it pretty much clarifies the situation for me Now i am thinking about an intake from my wall cavity.. it's cold out there between the bricks

I recently installed a new graphics card, HD7950, and ever since the fan in PSU has really been going fast when using demanding graphics. My Computer: Corsair VX550 550w XFX HD7950 DD Intel i5 3450 @ 3.1 GHz Asrock H77 pro4 MVP 4x4 Gb Corsair Vengeance RAM 3x SATA HDD, 1x SSD 3x 120mm Loud AnnoyingF...