Overclocking RAM raises vcore

[A1Mike_W]

I have a 5ghz overclock on 1.38v on my i5 9600k using a gigabyte ultra gaming z370 motherboard. I'm using 2x8gb of 3000mhz ram with it.

 

My problem is that touching any settings outside of the XMP basically screws with my vcore. Unless my RAM is at stock or on the XMP profile, my vcore will shoot up to 1.43-1.5v which is way too high for my liking and completely unnecessary. 

 

I know RAM might require you to set the vcore a bit higher to ensure OC stability but I've never heard of it raising the vcore automatically by 0.05-0.12v. Even if I manually set the RAM to the same values as the XMP profile the same ends up happening. 

I noticed that this vcore boost only occurs in windows - bios still reports 1.38v. I can confirm the readout from hwinfo in windows is accurate due to the temp difference alone - the cpu hits the 90's while idle and the fan speeds up accordingly.

Any idea what could be causing it?

[Cereal5]

Did you turn off multi-core enhancement? Also, there may be some overclocking software that comes with the board that might be messing with it in windows.

[A1Mike_W]

18 minutes ago, Cereal5 said:

Did you turn off multi-core enhancement?

MCE off, BCLK adaptive voltage off, turbo boost off, speed shift off, c states off, voltage optimisation off, energy efficient turbo off, etc etc. Basically everything non-essential off.

Altering memory values manually in any way shape or form whether that be increasing/decreasing voltage/timings/speed results in vcore shooting up to 1.5v or thereabouts. Only the stock speeds and XMP profile don't mess with it.

 

18 minutes ago, Cereal5 said:

Also, there may be some overclocking software that comes with the board that might be messing with it in windows.

Wouldn't there be at least one person out there who has this problem then? To my knowledge there have been no reports on this forum and looking for it on google didn't yield results. Most people don't report a link between RAM overclock and vcore with the exception that you might need to manually increase vcore to stabilise your OC after overclocking RAM (but that's not the issue here).
 
I'll get in touch with the mobo manufacturer, but in the meantime if you have any other ideas I'll be more than happy to hear them.

[RejZoR]

There are two voltages. One is for CPU itself and is it's operating voltage, the other one is CPU input voltage. I don't know how they are called exactly from top of my head, especially for Gigabyte, but CPU voltage isn't affected, VCore I think is CPU input voltage in your case which, when used with AUTO setting, it'll increase depending on conditions. Overclocking RAM nearly always raises that one and it's normal. You can try forcing it to be 1.4 or 1.45 and observe if stability with OC-ed RAM is affected.

 

Reason for this is, setting RAM to higher frequency stresses memory controller within CPU more than with lower clocks and BIOS automatically assumes it needs more voltage to remain stable. But it might not necessarily be needed in your case. Give it a try and use a RAM intensive test. I personally prefer ASUS's RealBench stability test with nearly all RAM filled up.