Z390 Master + 9900K too high temps

[Alunais]

Long story short:

Bought new Gigabyte Z390 Pro Wifi, Noctua NH-D15S, i9 9900K. In BIOS everything set to AUTO, launched prime95's torture test, the temps on all core went up to 100'C after couple of minutes. I found out that BIOS settings are too aggressive on AUTO to I switched LLC from Auto to Normal, and it helped a lot, same prime95 test and temps 65'C max. Then decided to switch to Gigabyte Z390 Master because of annoying coil whine, on the new motherboard the coil whine was even worse, but that's different story, what concern me the most is that same Auto settings (except for LLC to Normal) like on previous motherboard gives me temp up to 100'C. Can anyone tell what is going on ? It's same cooler, nearly same BIOS, just more expensive mobo and that temps are out of handle. I'm using Thermal Grisly Kryonaut, I think I applied it properly.

[shadowsports]

Greetings,
I just built a Z390 Pro - no Wifi

This is the first time in over 30 yrs I'm using water cooling.  I have been an "air" guy from the beginning.  I went with a small H80i v2.  Although I could do a 240 or 360 mm rad, I didn't want to bother.  While I acknowledge the efficiency of water, I've got $800 worth of GPU sitting below the water block and I still don't believe water and electricity mix  .  I'm sure this is because of my age.  But I went for it. 

I considered Noctua because of their reputation and quality.  Did your cooler come with grease pre-applied.  Or does it come with its own syringe? Can't comment on the amount of grease you applied.  You don't need much.  Too much will cause high temps, too little can cause 'hot spots"

Anyway what's more important is the information that's missing from your post:

-What BIOS rev are you running?
-What are your full system specs?
-What are you idle temps?
Are you OC on memory or CPU?
-Do your idle temps in the BIOS match what you see in the OS?
-Are you using a custom FAN Profiles?
>In the BIOS
>In the OS
>In SIV or Smart_Fan5? 
Are you using any 3rd party OC utilities?  (Precision, AfterBurner) etc?
Have you run with set up defaults and tortured the CPU?

The above questions are some of the most common areas that can cause issues with temps.  They can also give us a better picture of your environment.

Too many unknowns and variables.  Happy to try and help you investigate if you like. 

[Yemble]

Long story short:

Bought new Gigabyte Z390 Pro Wifi, Noctua NH-D15S, i9 9900K. In BIOS everything set to AUTO, launched prime95's torture test, the temps on all core went up to 100'C after couple of minutes. I found out that BIOS settings are too aggressive on AUTO to I switched LLC from Auto to Normal, and it helped a lot, same prime95 test and temps 65'C max. Then decided to switch to Gigabyte Z390 Master because of annoying coil whine, on the new motherboard the coil whine was even worse, but that's different story, what concern me the most is that same Auto settings (except for LLC to Normal) like on previous motherboard gives me temp up to 100'C. Can anyone tell what is going on ? It's same cooler, nearly same BIOS, just more expensive mobo and that temps are out of handle. I'm using Thermal Grisly Kryonaut, I think I applied it properly.

I can't advise you on the cooler you have, however, I can give some comparative AIO temps from my Master / i9-9900K rig featuring a Corsair H115i PRO AIO.  Coolant temps are 23C idle / 34C load (AIDA64 stability test).  CPU temps top out at 82C running AIDA64 stability test with no throttling.  AIO features four 14mm Corsair ML fans in push/pull configuration from the case front.  I am overclocking @5GHz.  BTW, I just used some cheap HY810 thermal paste from eBay... nothing fancy!