1,65Vdimm seems very low for me ;(
How could you for example run these Rams : http://www.com-discount.de/FMPro?-DB...=ALL&-FINDALL=
They need 1,8-1,9Vdimm to get these clocks.
But this would be impossible according to your post if you risk damage after raising Vdimm above 1,65..