Actually, if you are not OCing, you could even use ddr2-533 rams, with the e6600 cpu and 533 ram, you will be running 1:1 fsb to ram. Also if you are not OCing, try to get rams that runs on 1.8 or 1.9v. The intel board is very picky about ram voltages. BTW i have the d975xbx2 as well.