Hello, just got your email directing me to this thread
Have you tried the memory in slots 2 & 4? I think they are the primary slots, I cant remember if you need to occupy the primary slots prior to the secondary ones like the x58 boards, all the memory slots should be fine I have used 8gb of ram in this board with no issues (corsair memory & geil)
also make sure nothing is shorting the board behind such as stand offs in the wrong place, try the board on the bench
board was working perfectly mate, never had any issues with it at all, and yes the receipt is in the back page of the manual