Just done a quick bit of reading, it seems the standard voltage for DDR2 is 1.8v, with w.wv being used by manufacturers to effectively their product before sale. In theory the ram should work at 1.8v, but equally the board I have will let me up the voltage to 2.2v (found some people online with the same board that have done os, plus seen the bios pages that allow it

)
what do you reckon CD, worth a try?