Recently I bought a gigabyte GTX 580 OC to replace my old Ati 5870 . My system consists of intel core i7 870 cpu + 8gig ram , ASUS P55 delux MB, couple of 1tb HDD drives , 1 ODD and 7 Led fans , which are powered by a Corsair VX 550 watt psu ( single rail +12v, rated 41 amp ) . Now i never felt that my system would need more power hence i didnt change my PSU until now, as i read on Nvidia website that GTX 580 requires a minimum 600watt psu ! So i bought a new PSU gigabyte superb 720 ( a bad choice ?? ) because i was in a tight budget and thought this would at least serve the purpose and surely would be better than TT lite and TR 2 series . But i couldnt find any authentic review on this PSU in any websites, neither any recommendation or clarification of the quality of this PSU. Besides it has triple +12 V rail ( 18 A ) which confuse me about the max amp it supports over the +12v rails, however upon calculation it says 42amp . many websites says it is completely safe to use a gtx 580 with 550wtt decent psu . Which is exactly what i have too ( Corsair VX 550 ) . Now im really confused and need expert recommendation to pick the right PSU out of these two i have: Corsair VX 550 or the gigabyte superb 720 (610w ) ??!! Please note that i OC my CPU ( 4.00ghz @ 1.37~1.38v) have 4 stick of 1.65v ram and 7 pieces of 200mm led fans )