I just bought this
RAM, and it says that it should run at 1066Mhz, but it's only running at 800. I tinkered with BIOS a bit and set the voltage to 2.1V per the manufacturer recommendation. I also messed with the overclocking settings and it hasn't changed any. I have had no errors or blue screens of death, and I run Vista 32bit.
In addition I also installed my new AMD Phenom II X4 945 (3.0Ghz) and it runs fine. They recommended to get that in order to run the RAM I got.
My MoBo is an ASUS M2N68-AM SE2.
I'm at a loss here to get the most out of my RAM.