Have you tried 0.1V and 0.2V? If not do so. Also, please set "Performance enhance" to "normal" or "standard", and also you may try "Option 2" under "High speed DRAM DLL settings".
Always change one thing only at a time and then retest to see if it helps.
You can also try underclocking your RAM, go to "System Memory multiplier" currently set to "auto" change to manual and then you can control the multiplier which determines the speed the RAM runs at. I would try, say, 800 or 900 and see if stability improves.