Destroyed 3 Motherboards! need help with sandy bridge build!

[phantom123454]

Hello, i recently built a sandy bridge i7 2600k build, and have been running into problems as soon as i SLI. after playing some crysis 2 PC randomly shut down, checked components and narrowed down to everything working cept the mobo. went back to micro center and picked up the sabertooth (definitely looked more solid and capable of handling high temps). worked for a couple days, was playing some minecraft today(not performance demanding at all....) and it shutdown on me again... it's not booting up, i see a light on the mobo, but only for a couple seconds, then it fades.
Could my PSU be systematically killing my motherboards? i would have thought that if it was a bad PSU it would have just crapped itself... but now it seems that the PSU's still alive after eating my motherboards....

thank you

PSU 750 watt raidmax power supply, GPU= x2 msi GTX 560 ti hawk, mem= 2x 4gb gskill, destroyed motherboards = p67 asus sabertooth, and x2 MSI p67 GD.

 

[darkside_gamer7]

thought u said three mobos...lol...idk brother...psu sounds faulty or u got something screwy somewhere...but...i suspect faulty psu wiring...u buy used or new from box?

 

[phantom123454]

forgot to add, destroyed 2 MSI's and one sabertooth, all brand spankin new parts. Cpu, and mobo's from micro center, everything else from newegg.

 

[phantom123454]

*UPDATE

Ok so i tried an old 350 watt power supply, and i managed to boot to bios, it does shut down after a min, but i suspect it from not having a proper 4+2 power source to cpu, it has the 20+4 pin but not the other one... so i guess ill RMA the power supply, and get something heftier, and hope that'll do the trick.

i still dont understand how a power supply could eat a couple mobos and keep on shtting on em, without shutting itself off or something.

i was nervous on how to return a 3rd mobo to micro center, worried theyd finnaly not let me cause its gettin ridiculous. but good thing its the power supply then

Thank you!