I have been asked for advice at work that I don't know the answer too. We are tendering for quite a few work stations. They spec they want is a Xeon E5-1620v2 and 16gb of DDR3-1866. But a company has come back considerably cheaper but with only DDR3-1600 memory. They want to know if this will make much difference. My experience was back when DDR2 was the king, and overclocking my AMD athlon64, where you needed to overclock the FSB inline with the memory speed, so you either needed faster memory, or better quality memory. I am obviously quite out of date.
My current thinking is, the 1620v2 is a 3.5ghz cpu stock. It has a 35x multiplier, so its bus is 100. That ties in nicely with the DDR3-1600 memory which according to wiki has a clock of 200 (I'm presuming being DDR it'll be doubled into the 100 bus of the cpu). Is this miles off how it actually works?
The next part is the turbo boost. It goes upto 3.9ghz. Does it do this by increasing the bus or the multiplier, or something else? If it is increasing the bus then will the DDR3-1600 memory struggle, and I'd be better getting the DDR3-1866