Go to BIOS and manually set the voltage to be 1.5v
I mixed and match memory before and they're running fine. Bios will run it at the slowest timing. I think my timings changed even though both memory sticks have the same specs but I manually configured in bios.
Well tell us what happens after you change your voltage :P
@ wintermint - current congi is 6-6-6-18 and voltage is 1.92 (default voltages is1.80)..is there any problem if i increase this voltage from 1.80 v to 1.92 v...?