OK first of all check the packaging for the memory or the chip labelling itself should advise - for example it might say 2.1-2.3V. This is the correct tolerance your RAM is designed to work. You need to go into bios and find the option where you can change voltages / timings depends on the mobo and bios as to where it is but on my ASUS it's jumperfree settings option. You might (at a guess) find it is defaulting to 1.8v which might be cause of your problems (mine undervolts on auto and I had to manually set to 2.1v) Have a look around the BIOS to find where this is or read your mobo manual it should tell you. Make the change and put all other memory timing on auto spd for now (so it uses manufacturer settings preprogrammed on the modules themselves) Let me know how you get on....