Your 9900k at 5.0ghz and 1.31v seems normal. But I would recommend watching temps and checking actual voltages during loads with HWmonitor (bench/stress tests) to get a real values and those values will depend on load line calibration set in bios. Asus users seem to use a value of 6 I believe, but check around on that. I'd also look into using an adaptive value. As the core clock clocks down at idle, so does the core voltage.
 
Running 3000Mhz memory is overclocking the memory technically. Default is 2133Mhz.
 
Core voltage is a separate setting compared to memory voltage. Your core as you say is targeted to 1.31v but your memory will more then likely be at 1.35v which is normal.
 
Chris

tmmy34
Last question,i promise.
 
 I oc my cpu due to click: Asus 5ghz Oc profile. Then i apply XMP profile. Memory GSKILL 32GB 3000mhz.
But i saw that in UEFI CPU core/cache voltage was on the left : 0.935 and on right ( AUTO ).
So for stability i manually raise voltage to 1.3. My question is ,that this option PROFILE 5GHZ OC not changing voltage or what?

 
I would take a solid guess that the profile is adding voltage to Vcore for the OC. Also, setting XMP profile will apply voltages for memory OC (default at 2133mhz is 1.2v) to 1.35v (<---Solid guess). The XMP may as change the voltages on the CPU VCIO and VSSA to higher then needed values. Here are the voltages you should look for and the recommended values I'd use.
 
*CPU Vcore - 1.30-1.32v <---- Will need to check the LLC (Load Line Calibration) value and adjust for Vdroop/Vdrop. Maybe set to Auto with Profile selected.
CPU VCIO - 1.20v <---- starting point. At 3000Mhz memory, you maybe able to lower it to say 1.05v. Default value is 0.950v normally with no OC.
CPU VSSA - 1.20v <----starting point. At 3000Mhz memory, you maybe able to lower it to say 1.10v. Default value is 1.05v normally with no OC.
Mem Voltage - 1.35v <--- Normal OC'd DDR4 voltage and would just make sure this is the value.
 
*For CPU core voltage, set above values, download CineBench and HWmonitor(<-- good for checking lots of system temps/info):
 
https://www.guru3d.com/files-details/cinebench-15-download.html
 
https://www.guru3d.com/files-details/hwinfo64-download.html
 
Open HWmonitor and look for a sensor named VR VOUT. This is the voltage being applied to the CPU. I found on my Gigabyte Z390 Master, this value reads lower then CPUZ reads. Now open and run Cinebench CPU test and watch temps and Vcore and see how far it drops under load. My 9900k when using set Vcore will drop from a set value of 1.32v down to 1.26-1.27v under load. This is the Vdroop/Vdrop. This lower voltage value is what you need to watch. Some people's 9900K's need to be at 1.29v or slightly higher under load. This is where that LLC value comes in. if you set voltage to say 1.31v and its dropping to 1.25v Vcore under load and you have lockups or BSOD, I would raise the LLC value up one. I thought I seen Asus users using level 6 the most as a point of reference.
 
Important note, you don't need/want your Vcore to go over 1.40v. At 5.0Ghz you really shouldn't need any more then 1.32v I would guess.
 
Little video I found that may guide you through the process better,
 
https://www.newegg.com/insider/z390-9th-gen-cpus-a-step-by-step-in-depth-overclocking-guide/
 
Hope this helps a little,
 
Chris

Profile maybe using lower value then what you’re setting but if the profile is using a lower LLC value then this will cause Vcore to drop below stable voltage with your CPU.

So say profile is setting a value for Vcore of 1.29v but under load Vcore is dropping to say 1.25v, maybe causing your issue. So you raise 1.29v to 1.31v and now Vcore will droop to 1.27v now since you added 0.02v. That maybe a stable voltage for your CPU.

As long as core temps are good, I’d try and limit to 80-85*C max for core temps, then yea you should be good on Vcore voltage. You could try and lower Vcore down to 1.30v and re-test for stability. This will help lower temps. Shoot for the lowest voltage you can with no errors.

I would still advise to check the VCIO and VSSA voltages as auto values will set these too high and can shorten CPU life....

75*C for gaming is a little on the warm side for gaming.... For benchmarks or stress testing, that’s fine. For gaming, I’d aim for no more then ~60*C...

This will depend on what cooler you are using and how well it will cool the 9900k. What temps are you seeing under real bench for max values..???

Ok i make at start new overclock manually ( not automatic ) and lower voltage like 1.300v and its stable and have -5C lower degrees :)
All fine. So thanks for replies and help. Anyway voltage is fluctuating 1.296v-1305v . Load line calibration level 6. :)