memory - DRAM Frequency showing 800 instead of 1600

I am running a Core i7 CPU originally at 3Ghz overclocked to 4Ghz using a multiplier of x20 and a Bus Speed of 200 Mhz

My memory is 1600 Mhz OCZ.

I installed CPU-Z to see what is going on - but it shows me (under the "Memory" Tab):

DRAM Frequency 800 Mhz

Channel Triple - NB Frequency 3800.2 Mhz

So what is the actual frequency its running on then? I am slightly confused.

Answer

DDR (Double Data Rate) RAM is designed to transfer data twice per clock cycle. 800Mhz x 2 transfers per clock = 1600Mhz effective.

So the actual frequency of your memory is 800Mhz, it is however possible to transfer data at twice that rate.

Answer from here