Download memtest86 (free) and let it run for a few hours. Should give 0 errors.
I assume you have a 64-bit OS, your motherbord supports 2 * 8 GB and they are in the right slots (1 and 3 or 2 and 4 most likely).
I've upgraded my RAM today from Corsair Vengeance DDR3 2133MHz (2x4GB) to Corsair Vengeance DDR3 2400MHz (2x8GB). It's only the two 8GB sticks in the board at the moment.
After around 15 minutes after starting the system up, I will generally get a BSOD saying, "System Service Exception". Does anyone have any idea why my system would be doing this?
As the only thing I've changed is my RAM, I assume RAM is the culprit of this?