I'm guessing that set of ram has D9 Micron IC's? If so, it should be possible to run 800mhz at 1.95v and if they won't you have to run them at 667mhz. With 2.2v u can reach up to 1200mhz, that is, if they have D9 Microns on them.
Is the board you're talking about the Biostar 560 in your sig? Update (Flash) the BIOS, the one that comes with the board has very limited memory options. The most stable BIOS for the board is the August 3, 2007 release, but last I checked that's no longer available on their web site. I'm using one from January 2008 on this board, and I can go up to 2.4v on the vDIMM. It has a few issues though, my CPU Multiplier is locked at 10x no matter what I choose (which is fine, I wanted 10x anyway lol), the tRAS is locked at 18, and the tRC is locked at 26. The timings are kind of annoying, but I was only going to run them at 15 and 24 respectively so not a big deal. Maybe you'll have better luck than me.
EDIT: Biostar TForce 560 BIOS Updates *NOTE: the only way to update the BIOS on this board is with a floppy drive and floppy disk. Just download the file "N56BA110.BST" from that link to your desktop, then drag/drop it onto a floppy disk. Restart the computer with the floppy disk in the drive and go into the BIOS and choose their BIOS Update menu.