qwaarjet
Does anyone have any suggestions?

I assume this becomes non-issue if you disable system from going to sleep, correct?

qwaarjet
Well, I was so fed up once I disabled sleep during the day but I noticed a couple of times where the that certain CPU core maxed out once again after several hours (maybe 6+?)  I've worked from home that past 5 years so it's probably why it's very noticeable to me.  

 
 
I haven't experienced this in my 10900 build but I'm not using it a lot yet so I can't tell is that because I'm not watching over it close enough or because everything is good (to knock on the wood its the later). One thing I do differently than others is disable fast boot in BIOS and I hear that is one of common culprits. My wait states are disabled in BIOS and I have also disabled hybernation in Windows.

Sorry for the late response, got hit by a hurricane. 
 
All devices are good in device manager. I've done clean installs using all EVGA provided drivers. I've done clean installs using all MS Update provided drivers (except for the handful it can't find) and I just force installed the latest W10 update hoping for something.... I'm thinking about buying an older CPU so that I can use a pre 1.19 BIOS. Never had this issue prior....

When you say ‘clean install’ do you mean fresh clean install of Windows 10? My recommendation would be to download the Windows 10 Image and all drivers. Than disconnect the PC from the internet and do NOT reconnect it. Install Windows 10 and all drivers than reconnect to the internet, you are doing this to avoid getting the default Windows drivers.

qwaarjet
In case anyone searches and has a similar problem, I swapped my motherboard for an Asus rampage vi extreme omega and wouldn't you know, no more ACPI.sys/cpu core maxed out issue after sleep. Exact same hardware, same windows install, didn't change a thing other than the motherboard. Problem with the motherboard/bios, I should have swapped long ago.

That is good to know, thank you for sharing. FWIW, I still haven't observed high CPU utilization by ACPI.sys (or anything else) on my system but my system is configured not to go to sleep (I don't like "sleep" on my systems).
 
So for those that do experience same you did but don't want to / can't change mb they might try to see whether configuring system like I did (no fast boot, no sleep, no C-states, no hybernation) will work for them.

ty_ger07

ZoranC
So for those that do experience same you did but don't want to / can't change mb they might try to see whether configuring system like I did (no fast boot, no sleep, no C-states, no hybernation) will work for them.

Poor mother earth!

LOL I think Mother Earth has much bigger issues to deal with than my C-states :) Besides sleep setting on my system wouldn't save -that- much, it is either in constant use or completely turned off.

ty_ger07
My PC idles at around 45 watts at the wall according to a kill-a-watt meter, and then sleeps at less than 4 watts.  What does yours idle at?

My idles at practical zero. When my PC is on it is fully under load, otherwise it is completely turned off, I don't leave it idling.
 

ty_ger07
Sleep and C-states make a big difference in needless power consumption.  And when you recommend the same to others, it is compounding.

 
It is my understanding they make a difference only when CPU is idling / can throttle down or when system can go to sleep, otherwise they don't make difference so they wouldn't result in any difference for me. Am I incorrect about that?
 
Also, please notice I haven't anywhere recommended my settings should be used by everyone. I have offered them as potential workaround to try for those that have experienced similar issue as op. Considering how "many" are reporting this issue (so far I can see just one) if they end up using what I do can be hardly qualified as "compounding".
 
Plus, let's face it, people that buy things like X299 Dark do not later run them at balanced power mode either. If one placed priority on power consumption he wouldn't be overclocking his gear.

ironage
... there is no need for useless power draw, which only transfers into heat.

 
Is there a need for useless power draw? Absolutely not, there is nothing wrong with that -generalized- statement. How much of power draw ends up useless and how much of total effect everyone that might be experiencing this issue would be contributing if they tried my workaround suggestion? That is completely different question. Like I said, I believe answer on first one is -it depends- on utilization pattern (so it can vary on case by case basis from huge to insignificant) and answer on second one is not that much because we are not seeing people reporting it around (just one so far).
 

ironage
we don't need inadequate workarounds, we need a better UEFI/Bios.

 
I absolutely agree that -in general- we do need better stuff. However, I believe that -in the meantime- people do need workarounds when they have an issue. Having a workaround while waiting for a resolution is much better than having nothing.
 

ironage
... why you keep defending unnecessary faults in EVGA products ?! 

 
I think you are misinterpreting my words. You need to notice there is a huge difference between suggesting a temporary workaround and saying "this is a solution".
 
Also, if you knew me little better you would know I am the very last one that would defend  fault in anyone's product and don't hesitate expressing my opinion on one. Anyone at EVGA that talked with me so far on issues I came across can confirm that.
 

ironage
i will wait for a better bios for another two weeks and then i am done with it and sell the 2nd dark, if EVGA prefers snoozing.

 
If my experience is any indicator I wouldn't be holding my breath if I was you. My ticket for what I have experienced with my 2080 has been opened for month now with no updates even though everything indicates that has been known about for long time. That is one of the reasons why I didn't go and order 3090 when they were announced.