Actually 1.65 is high for sticks that are 1600 or even 1866 and can be indicative of weak Memory ICs, has nothing to do with OCing the DRAM, 1.6 1nd 1.65 is basically the standard for sticks/sets at 2133 and up....When you OC DRAM you normally need to take it to a higher voltage and if these are 1.65 and 1600 1866 you don't have much wiggle room to OC...Also if Intel the max they recommend for 1600 sticks (entry level) is 1.5-1.55