Follow this guide!  Linuxrouter put this together quite well.  I've been using it to redo my OC.  I must say that I'm getting way better results using it then going the way we all used to go.
 
Give it a shot.  I will say you won't be disappointed!

My overclock is rock solid, I've just been seeing a lot of people using less IOH and ICH voltages than I was using, and I want to make sure I'm not using too much.
 
I remember someone stating a "rule of thumb" in regards to these three settings based on how many gpu's you were using, and that's what I'm looking for.
 
What I originally used to adjust my settings was a guide someone posted a long time ago about how to get the most of your gpu's by increasing these three voltages in a very systematic method, which I did, and got a good bit higher 3DMark score, almost 1,000 points more actually, but I still think those voltage were too high. After tweaking, I got my highest score using these:
 
IOH Vcore: 1.375
IOH/ICH I/O Voltage: 1.65
ICH Vcore: 1.300
 
As you see, those voltages are extremely high. Even though they gave me the best gpu performance, I reduced them back down to what I mentioned in my original post just out of longevity reasons.
 
Anyway, I can't remember who it was, but one of the more prominent members here posted this "rule of thumb" to set them to based on the number of gpu's, etc. and that's what I'm looking for.
 
EDIT: Oops, nevermind. HalloweenWeed was answering while I was typing. Thank you VERY much. That's exactly what I was looking for.