Problems OCing With 4 Sticks of Ram

I had no problems overclocking my Opteron 165 to 2.7 ghz with two sticks of RAM but now that I have 4 sticks I can barely run slightly above the stock CPU speed.

Setting the timings down does not seem to gain any stability whilst overclocking but read a comment that the Northbridge is being taxed more with 4 sticks of RAM and believe this could the problem.

Memory bandwidth is the least of my concerns and games require more than the 1.8 ghz my Opteron provides at default. I need to get it up to 2.7 ghz again if even at the expense of memory bandwidth. 300x9 was stable with 2 sticks. Are there any suggestions on how to circumvent this problem?

EDIT: Dividers were used and memory speed was slightly underclocked

My setup consists of the following:
DFI Lanparty Ultra-D (Nforce 4)
4 x 512 PC-3200 DDR1
Opteron 165
8800 GT

Try increasing voltage to the memory and northbridge. You could also try changing memory command rate to 2t. See if any of that helps you.

Increase the northbridge voltage.