Like others have said above, you could try just using one stick and so some stress testing- reboot if it passes then manually dial in your memory kits settings and voltage as stated in your memory kits manufacturer specs then redo the tests. If it passes again, redo the tests but with two sticks and be sure memory placement is at the reccomended slots for dual channel as stated on your motherboards manual.
Would recommend you add using aida64 for full system stability tests. I've had new builds that I Overclocked before that had random App CTD or system reboots while using blender even though it had already passed 3hours of prime/mem tests. It would only fail after 2 hours of full system stability stress test from aida64, and it will usually tell you what test it failed at.
If all else fails and your still getting errors even after testing with a new memory kits, you could try testing with an older bios as your last resort, one way you could do so without having to reflash is by using your bBios since updating your bios only updates your mBios (unless your at bBios and updated that one instead) so your bBios should still be using an older one.
Gigabyte boards usually have dual bios (mBios and bBios, led indicator located near the PCI-e x16 slot tells you what bios your currently at) and have a physical switch usually located at the bottom part of your board (check your board manual).
Be warned though that switching bios takes time while it does memory training at first boot, and may do a couple of reboots before its done. May also loose display signal even when windows is clearly running normaly, in which case you may have to reset your PC using the power switch before it will show your display normally again.
