Yes check your RAM voltage in BIOS.
I see you said you have G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 but there are different modle numbers with different timmings and voltage please check your receipt.
I checked and the volatge was going up and down at around 1.5 to 1.6???
This is the model... Model F3-12800CL9D-4GBRL