Summary: i bought the corsair hx1050 80+ gold to power x2 gtx 780's in sli and my i7 2600k . i only had this power supply for one week before i returned it . the reason i returned it was because when ever i was gaming it got very loud it got so loud that i was scared some thing was wrong with it . and it was also giving off a faint smell of plastic burning .
Summary: ... I've tried to turn my new Radeon 7970 on by using the optional cables (modular) that came with this PSU. I had to skip using this cables and used the ones that are attached in the PSU, and only after that my 7970 worked. I've stoped doing tests but I think I will have some problems to make another 7970 card to work in crossfire mode because I'm not sure if the PSU is really working 100% to support 2 graphic cards.