How to tweak Memory Controller Voltage?

[Hari_Seldon]

This is a continuation of stabilizing my memory at faster speeds than 4800MHz:  https://rog-forum.asus.com/t5/intel-700-600-series/rog-strix-z790-f-wi-fi-i-stabilizing-128gb-at-560...

I am been messing with my memory in hopes that since it was added to the QVL, that I could get it to work with the higher XMP speeds.  I think that I could increase the Memory Controller Voltage yet am unsure about the safe way to do that.

• Increase in what increments?
• What is the maximum safe voltage?
• Is the voltage affected by the use of 2 vs 4 modules?  More of curiosity.
• Will running at that maximum cause it to degrade faster and by how much?  If the memory dies one day sooner, that is not as much a problem as if its life is cut in half.
• Does anyone ha

On a related note, I did run across a possible bug.  Enabling XMP I and trying the various speeds gives me interesting MC Voltage values.  While 5200 results in an occasional error in memtest or application compilation, 5600 spews them.  I think its choice of MC Voltage is wrong.  It also would explain why getting to POST at 5600 can take a long time or not work at all.

No XMP	1.225
4800MHz	1.332
5200MHz	1.384
5600MHz	1.225

[Smugller]

If you want to push it to the limit or stabilise, you should play with voltages of below:

CPU:

IVR Transmitter VDDQ Voltage (also known as CPU VDDQ / TX) 

Memory Controller Voltage (also know as CPU VDD2 / IMC)

DDR5:

VDD Voltage

VDDQ Voltage

Voltages also depends if you've made undervolt on your CPU.

[Hari_Seldon]

From reading several sources of information, I am *so* thankful that those values go by many names.  If everyone used the same names, it would makes things too easy.  ‌😉‌

Do you know where I can find the safe limits on those voltages?  Which voltages are tweaked first?  In which direction does undervolting affect the voltages?