So if yiu put in a pair of 1.65V high frequency sticks, the mobo will basically "clock them down" to preset values they can safely run at to boot. That much I get.
Read a lot today around this board and others and found much useless advice given, like "nearly all DDR3 are now being produced in 1.5V" and "Stick to 1866Mhz RAM, no point in spending more money on faster RAM on 1155/1150 as it gives you no benefit". At least now I can spot some of it.. ;-)
Since CPU-Z was mentioned, I ran that on my old Core2 Duo E6600. First shock was to see they were running at 1.8V, until I remembered that was exactly correct. Then TAT reported idle core temp at 52C...ugh. And the CPU is flipping between 1600 and 2400 MHz...oh my...
Well, tnx for all the help, Tradesman...I'm learning a lot.