I have bought today a set of Dual Channel Geil 2x4GB DDR3, 2133MHz, Evo Corsa Memory Kit and i have an ASRock P55 Extreme motherboard. I have tried every option (including setting the 'Easy Memory OC' to 2133 MHz or using the XMP Profile, adding that the shown voltage is 1.65v) and in each case, the PC restarts, and when it has to start, all i get is a black screen. I have to reset the CMOS, using the button on the motherboard.
I have tried even the 1600, 1866 and 2000 MHz versions but neither works. I think i am missing something vital. At the moment, i am running on the safe 1333MHz value on CL5 Timing (if i remember correctly), but i want to use them at their full capacity.