Im pretty sure they are the same kits. I originally only ran 1 4gb stick (odd number) and maybe about 3 months ago I bought another 8gb because it was so cheap on newegg. But ill try take out 1 4gb stick and see if that solves the problem.
Yeah, definitely try taking out the original 4GB module to see if that fixes it. It may be the very same RAM, but you're running a Dual/Single Channel config that can cause issues and it's not perfectly matched, for sure.