Ok open question to all, but Ideally I do need a final answer from a well informed person. "There shouldn't be more than a 0.5v difference between QPI/Vtt and DRAM voltage." Where did you get this info from folks, as I've come across it all over, but haven't found a source so to speak? I've found places that also said "no more 0.25 and 0.05 Volts difference between the two", and I've seen it more than once, too many times possibly, misquoted as Being Vcore and QPI that shouldn't be separated by more than 0.5V. Here's what I know, 1.65V is generally considered max for Dram Voltage by most people. I know Intel said this, as have the Memory Manufactures(It's on their websites). This is because the i7's have an onboard memory controller as oppose to being on the Northbridge Chipset where they use to be. I also think I understand that the QPI Interface essentially links the CPU to the Northbridge. Where PCI Express Bus starts etc, and then it's a short hop to the ICH on to Sata, USB , audio controllers etc. The other thing I know is that when running higher than stock Memory like say 1600. QPI/Vtt (goes by a few different names but same thing) may need to be raised to as high as 1.35V when overclocked, or even if the CPU is kept at stock speed as in no Bclk change. (Info from Memory manufacturers websites). Ok so 1. I don't quite get the link between QPI/Vtt and Dram? and 2. if max Dram is 1.65V or even if you push slightly past this, stock QPI/Vtt is 1.2V with 1.35V or a bit more as max, and I believe this 0.5V difference, hold on let me do the math here... 1.65-0.5 = 1.15V wow that's under stock voltage, I don't see how you'll ever end up in a situation where there's more than 0.5V difference between QPI/Vtt and Dram.? So why all the fuss, did some poor person blow himself up, when he accidently set these wrong!
I got the information from here http://www.bit-tech.net/hardware/cpus/2008/11/06/overclocking-intel-core-i7-920/3 Intel won't give a straight answer but did say when I asked about a QPI voltage of 1.6v 'Since Intel does not support overclocking, there is no information regarding this matter. The default value is 1.150V, any value above the default will override the factory settings, running your processor out of specifications (overclocking). Bear in mind that the QPI/uncore voltage is not the same as the Vccp or VID voltage of your processor. The VID voltage range for Intel(R) Core(TM) i7 Processor I7-920 is from 0.80V up to 1.375V. The QPI/uncore voltage is by default 1.150V. Apparently your motherboard auto adjusts all the settings every time that you modify the memory speed. Adjusting the appropriate QPI voltage and memory voltage. If your motherboard manufacture told you that the settings are fine and the performance of your system is stable, you can keep running those settings.'
