Question CPU temperature different at each boot

[Shervil]

My setup:
MOBO: Asus Z690 TUF GAMING PLUS D4 (BIOS 2103)
CPU: i7-13700KF (stock)
GPU: MSI RTX3070Ti Gaming Trio
RAM: Patriot Viper 2x8GB 4000MHz (no XMP enabled)
PSU: Corsair RM850W
Case: BeQuiet Silent Base 802W
Cooler: Arctic Liquid Freezer II A-RGB 360mm
Drives: Samsung 980 PCIe 4.0, Adata Gammix S70 PCIe 4.0

Hi,
I have a weird problem. When I boot up my PC, CPU temperature is totally different at each boot. Sometimes it's normally 30C but at the e.g. 3rd boot it's 90C and
it's causing the fans go crazy (~2000RPM). I checked the AIO tubes - they're something between cool-warm and i can feel the liquid is moving (same situation for both temperatures). Freezer II is connected to CPU_FAN connector.
Mounted and cleaned AIO twice. Thermal paste is Thermal Grizzly Kryonaut. I even managed to install Windows and I checked in HWInfo that temperature is something around 105C at desktop (in BIOS it was 90C).
The other time I booted it up it was only ~35C (same in BIOS). CPU core voltage in BIOS is somehwere within 0.9V - 1.2V. I'm wondering if it can be the CPU temperature sensor on MOBO that can be broken and is giving the wrong numbers.

What do you suggest?

BR
Shervil

 

[Darkbreeze]

Can you post some pictures of the inside of your case showing where the AIO is installed and how the lines are oriented?

This sound like possible an air bubble issue or a water/pump block that isn't well seated, but hard to say. Did you just build this or has it been working normally for a while and only now started having problems?

Crazy as it sounds to ask, you DID remove the plastic cover on the preapplied thermal pad on the bottom of the water block AND if you applied thermal grizzly, you DID remove all of that preapplied pad before applying thermal grizzly, right?

How much Kryonaut did you apply when you did the installation? There is no ability to move the water block once it is fastened to the backplate right? Like, if you grab hold of it and twist slightly, it does not give and there is no slack?

Do the RPMs for the header the pump is connected to look normal in the BIOS and is the pump header set to 100% speed at all times, NOT temperature controlled with a curve?

 

[Shervil]

Thank you for answer

1. I'll post pictures tomorrow.
2. Just built the PC. Maybe if it's air bubble I should shake the radiator while the pump is on?
3. Removed plastic cover and cleaned both processor and heatsink with alcohol.
4. Applied something like pea grain amount. It doesn't shake while i move it.
5. It's controlled with the temperature curve.

 

[Darkbreeze]

Not "shake". What you can try is, with the unit running, lift the front edge of the case backwards until the top front corner is basically the back rear corner, or as far back as you can get it to go without the cables stopping you. Then back down. Then lay the case over, slowly, on it's side, and then the other side. If there is an air bubble, this will often help it to escape from the pump and get back to the radiator where it belongs.

Do NOT control the pump speed with a temperature curve. Set the header the pump is connected to to full speed 100% operation at all times. Radiator fans should be temperature controlled but the pump should always be at 100% speed. Or at the very least, make the starting point for the pump about 80% speed and then set the curve so that the pump is running at 100% speed anytime the CPU reaches 80°C.

 

[Shervil]

Sorry for the late reply. I didn't have time to reply faster.
First of all I wanted to clarify the temperature curve aspect. In Liquid Freezer II you have only one 4-pin PWM cable which is controlling the fans (from what I found in the web the pump is working on 100% all the time). That's why on the pictures below the pump speed is N/A. Also don't worry about the PWM cable connected to CPU OPT FAN becuase i checked both CPU FAN and CPU OPT FAN.

Here are the pictures of BIOS and inside the PC:

https://imgur.com/a/fyAbf7k

View: https://imgur.com/a/fyAbf7k

Tried your troubleshooting steps but nothing has changed.
Do you think RMA is good idea?

 

[Darkbreeze]

Which revision of the Liquid freezer II A-RGB 360mm cooler do you have? 1, 2 or 3?

 

[Shervil]

Rev. 3

 

[Darkbreeze]

Huh. You're right, that cooler has just one cable that serves the fans, pump and VRM fan. I'm not sure how they manage to not exceed the amperage limits on a typical PWM header while providing sufficient power for all those components, but I guess we'd know by now if it wasn't a satisfactory arrangement. I guess. LOL.

So, try to see if you can cure the problem by trying to rock/adjust the unit like I explained above, with the unit running, to see if there is an air bubble. The installation the way you have it is fine, since the radiators lowest point is well above the pump, but still air can get trapped at any point from manufacture to installation so always worth trying. If that doesn't work, then I'd RMA the cooler. At only .728v there's little chance you should be seeing 88°C temperatures, and that can pretty much only be an air bubble, faulty pump, faulty CPU or fans that are not working correctly.

 

[Shervil]

Thanks for your time then I think I'll RMA the cooler.

 

[Darkbreeze]

I mean, I think that's the best guess right now.