Yes, I would start testing all things of yours that gigabyte didn't have when they tested, start with the easiest and work your way up.
My Order would Be:
RAM - Test 1 stick at a time, full pass with memtest at 800mhz.
Video - put a cheap PCIe - PCI videocard in
PS is your best bet and you're testing that now.
Last CPU, make sure all temps are good, seated properly and if all else fails, borrow another to try.
Make sure the aux power cable is plugged into both your MB and Videocard.
Try another HardDrive/Cable(s).
Not sure if I would trust that RAIDMAX PS though, I mean Modular to me is a gamble anyway but add in the $70 pricetag and woah.
If All else fails I would test with another Brand of PS.
Other than that, make sure board is not grounded to case(No steel touching any part of the board except the screw headers)
Best of Luck.