I hope this is not the same problem I had with my Motherboard (GA-Z68X-UD3R-B3) When I installed my ram chips , which are the same as yours it would only work on slots 1 & 3 not 2 & 4, if all slots are filled my computer keeps rebooting itself. i took it back to the shop I purchased it from, when they found out I installed the CPU they removed it & told me i had damaged pins in the CPU motherboards socket I informed them that was how I bought it from you.
they said I damaged it so warranty is void, no amount of explaining to them that i did not do this helped. Any way to cut long story short purchased a new board from a different company had them open up the box check the pins & install my CPU, now all 4 ram sockets work, running 8 GB.
Actually had this problem put on this site a week ago some one suggested it might be my CPU socket which it was. have noticed this problem on many sites since, was wondering if its a Gigabyte quality problem if so I hope i can get a refund on my old board $178 AUS.
Hope this helps.