Is the 50c for at-rest or when you are putting the rig under-stress when you took that reading? What method did you use to get that reading? What are the specs of the rig so we know what normal is for that CPU and motherboard?
I suggest you download and run
SensorviewPro and see what it tells you. Do try it when first put on and then after playing a game and report back with temps and voltages.