Quote Originally Posted by T_Flight View Post
Yes, it has to do with the physics and what these new CPU's and the Mem Bus and COntroller can withstand. It's a differential voltage problem. If you start getting away from a .5v diff between the QPI/DRAM (Vtt) and the DRAM voltage it could cause damage. This was Explained by Dr. WHo ina post on here early on right around release time. He also said that like all OC'ing to do so at your own risk.

In this case, I'd say the less diff the better. Since we usually deal with around 1.65v on the DRAM, we need to keep around 1.3-1.4v on the QPI/DRAM. 1.35v on the QPI/DRAM is the Intel max spec if I'm remebering right. I have 1.3v set in mine right now and it's fine on the rig in my sig. Be careful with Vtt though, becasue there is a limit, and if you go too high damage to the IMC can result. I don't think we know where that line is yet, but some have been running slightly over spec voltages with succsess although it doesn;t mean they'll be able to do that for long periods of time. It's all about the risk you are willing to take.

I'm on the more conservative side, and I'm very careful what I say about voltage because voltage can cure some problems, but it also kills these parts if one goes to high. AFter a bunch of reading, I've developed a feel for it, but I'm very careful what I do.
Many thanks for the eplanation and for giving your reference voltages. I'm on the conservative side as well but was hoping to achieve 4Ghz with my 920. Unfortunately I'm still waiting for some WC'ing components and wiring (8-pin extender). I hope to receive all these components this week, so I can assemble everything this weekend and start to play with the settings. I just wanted to make sure that I don't screw up my new components immediately by not complying to the 0,5v differential.