Using 4 x2GB of identical 2 x 2GB memory kits can sometimes be difficult, using two different kits is often harder.
Are you using 5-5-5--12 settings or 4-4-4-12 settings.
You might need to set Dram Voltage to 2.20 volts or slightly higher for 8GB.
MCH Core = 1.20 - 1.30 might be required, too low or too high can cause boot loop problems.
You should disable Auto Restart when a BSOD occurs and report the error message and bug check code, for example 0x00000101
Download and install Resplendence Software - WhoCrashed, automatic crash dump analyzer freeware and post the BSOD report. Read the documentation at the bottom of the web page.
Also post a CPU-Z SPD screen-shot for each memory kit.