I would change the Vdroop so the Vcore doesn't go up so much under load.

Whichever way you have to change Vdroop, increase or decrease the value (however it works on that board), to get the Vcore down more under load..And make sure you have the latest mobo BIOS installed.

Still testing but looking like upping the vdroop from +75 to +90 (max) is going to make the difference for me.
Have been inching up the vcore and testing, up to a more reasonable 1.28v now and core temps are much better. 
 
I first tried going the other way with the vdroop as I was already at +75, but that was throwing even more voltage at the problem which was not good.
 
I still do not understand what has changed over the last few months, and why I am having to make these changes now - all very odd I must say. Why in the world a system that has been stable all this time all of a sudden I had to lower and lower the voltage because it was suddenly apparently throwing more at it with the same settings.

This is about the craziest thing I have ever seen.
I could not get stable with +90 vdroop, threw as much voltage at it as I was comfortable with.
So I went back to +75 vdroop.
Now have my vcore all way back down to .990v. It is starting to look stable now, although it is still throwing little more voltage under load than I would like - peaking around 1.38v with core temps in mid to upper 70's..
 
Will keep tweaking and testing, but man this is frustrating as all get out. Just makes no sense at all.
I may end up just lowering my overclock from 5.1 on all cores to 5.0 on all cores and see what I get.
 
Edit: I now have vcore down to .982, so far seems stable at my 5.1 but vcore still spiking under load up to like 1.38, so core temps still in upper 70's. I will see how it does in my gaming, may end up lowering the vdroop some as well.
 
Edit 2: Vcore down to .980 now, still seems stable so far in testing. Core temps more reasonable in low 70's. 
So for whatever reason, my Z390 Dark keeps putting more voltage in my vcore apparently, at least on my previous settings - and I find out by monitoring my core temps and noticing them getting up into the 80's which is unusual for my rig. I then find out I can lower the vcore even more to account for this and get it back to where it about was temp and stability wise.
 
 I don't think I could get more baffled. It does though cause me concern on what in the world is going on with my motherboard/cpu.
When I first built this rig in Jan. think I was running at 1.28 on the vcore and everything was great at this overclock. Over time I apparently have to keep lowering my vcore setting to provide the same end result.
 

I keep lowering vcore, down to .970 now, and voltage/temps rising during stress.
I think I need a throwing in the towel emoticon...
 
Edit: It does not appear to me, lowering vcore is really changing my voltage any more. Have it down to .950 now and while stressing it is still pumping up to 1.36-1.38 with core temps peaking into mid 70's. 
 
Edit 2: Down to .92 vcore and +75% vdroop, appears to be very close now to what it was running previously.
Think I am good for now, until it decides to change once again. I still have a bad feeling about this.

kelkel1
I presume these are BIOS voltages?
 
Have you tried using a DMM to check the actual voltages at the test points?

Yes bios voltage, and voltages read out on monitoring software whist stressing - CPUID.
No I do not have a DMM.

bp7178
IIRC, CPUZ will just give VID values not VCORE when used with the Z390 Dark. 

Ok thanks, will check into the differences.
I am still quite perplexed though over the continuing need to lower my vcore in bios under what it used to run at.

It sounds like the motherboard (or the BIOS).
 
If you had another processor to swap in, that could help narrow it down.
 
I would probably submit a support ticket request.

After most of the day yesterday tuning and testing, I seem to have found the sweet spot for me at
1.29v and -75% Vdroop.
Core temps whilst stressing around 70-73c, spent today gaming and core temps never even broke 70c, they were in mid to high 60's. Even better than I previously had before all this started.
 
So the Override Option is golden for me, won't be doing the adaptive any more, it got to where it was acting nuts.
Hopefully the voltage in Override option stays consistent.

thebski
Have you flashed the bios recently? I only ask because I had a Dark board and 9900KS and it was doing similar things on Auto and Adaptive voltage settings. It was is if I had no voltage control. Something happened that killed the CPU and the board so I am currently waiting on replacement parts so can't really test anymore atm. I only tried bios 1.07. I didn't know if yours changing behavior coincided with updating the bios. Maybe there is a bug in 1.07.

Mine did it with both bios. Even tried re-flashing the latest bios which did not help.

kelkel1
Have you tried the XOC BIOS?

No not familiar with that, am on latest official bios 1.07.
Pretty happy with where I am now though after changing to Override on my voltage setting.

kelkel1
XOC BIOS offers quite a few extras, but not sure it would help with your issue.
 
It does appear to be quite stable, for me at least.
 
https://xdevs.com/doc/_PC...E399_flashtool_093.zip

Thanks but as I said, since changing voltage from adaptive to override, everything working swimmingly for me - at least so far. Not going to mess with it at this time.