I haven't tried loading default settings but I've been having the same problem since I bought this rigg. I don't think it's ram related because I had the same issue with another corsair dual channel memory 4gb 1600mhz before I received my dominator quad 2133mhz. This occurs even when the pc is not oced. Hopefully HiVizMan will identify the issue. Unfortunately I cannot swap my cpu. I'm using optimized default settings with tweaks.