Question 5900X overheating with 80c + temps while basically idling ?

Oct 18, 2021

I'm having troubles with my 5900X overheating, I'll acknowledge straight away I am in a SSF case but looking for other suggestions before giving up on SFF.

System specs;
CPU:- AMD Ryzen 9 5900X
CPU Cooler:- Kraken Z53 240mm
Motherboard:- Asus ROG Crosshair VIII Impact (AMD AM4) DDR4 X570 Chipset Mini-DTX Motherboard
RAM:- Corsair Vengeance LPX Black 32GB 3600MHz AMD Ryzen Tuned DDR4
Graphics:- EVGA NVIDIA GeForce RTX 3090 24GB XC3 ULTRA GAMING Ampere Graphics Card (One of the few cards that would fit in the case)
PSU:- Corsair SF Series 750W 80 Plus Platinum Modular SFX Power Supply (CP-9020186-UK)

Additional system information:
Case :- Ncase M1
Fans: 2x Noctua NF-A12x15 PWM set to intake from bottom
Kraken set as exhaust from the side.
Thermal paste: Thermal Grizzly Kryonaut 12.5 W / m · K 1 g thermal grease (-200 to 350 ° C)
BIOS version: 3204 last update 25/01/2021

Current temps as I write this post; 85 C no other applications running other than hardware monitor and NZXT Cam.

Reapplied thermal paste this weekend, has always run hot but I can't seem to get it consistently working well.
Are you sure the cooling plate is flush against the cpu? 80c idling says the heat is not being drawn away by the cooler. Either plate is not flush or the cooleris not working correctly or has a has a bubble in the pump area and water is not flowing through the tubes. When the pump has run for a while feel the tubes. Are they both warm, one cool, or both cool? And what temp is the pump showing?
Oct 18, 2021
Hey @Fix_that_Glitch! Thanks for the response.

I double checked but the cooling plate does appear to be flush with the CPU. In relation to pipes, one seems to be cool and the other warmer after a couple of checks.

In NZXT CAM the liquid temp for the cooler appears to be holding temps around 36c and 40+ c when under a bit of load. The computer is also crashing due to CPU temps from time to time. When it crash earlier the CPU temp was 79, the CPU package temp 90 and the NZXT display also showed 90 and I was browsing the web whilst on a discord call, not exactly high load!

The pump is making a rattling sound when turned up to 100% despite not being very old. Does this give you any further indications?
Yes so either you have bubble in the pump like I said or your pump impeller, the part that spins around, may have broken in a spot/s. Is the top of the radiator higher than the pump? Also while the cooler is running CAREFULLY tilt the computer case from side to side and see if the noise changes or goes away after a few tilts. If it goes away, then check the temps to see if they are going down. If the Nosie doesn't go away try tilting the case a little more steeper from side to side to try and get the noise to go away.