My CPU to goes to 100% and I can't figure out why

For a bit of background: Age of Mythology on steam was launching using my IGPU instead of my NVIDIA card, causing the screen to stay black. In the Proton log it showed that the NVIDIA card was being recognized, but it was still reverting back to the IGPU. I think that’s a proton issue, so I will post there about that as none of their solutions worked. In the mean time I found that disabling the integrated graphics on my MSI motherboard’s BIOS fixed that problem. (There are 3 options: Disabled, Forced, and Game Mode)

My problem now is that after some time the CPU will ramp up to 100% usage and the whole computer will freeze for long intervals with short intervals of stuttering usage.

I am unable to see what process is using up the CPU, the KDE System Monitor only shows 100% usage and doesn’t show that any process is using up more than normal. I’m not new to Linux, but I am not a power-user. Is there some reason this would be happening or some way I can find out what’s causing this to happen?

Update: It just happened while I was playing Doom 2016 with Integrated Graphics in Game Mode in BIOS , so I’m not sure what is going on. I installed with rEFInd as my boot manager, but I can’t imagine that would be the problem. I did use the open source NVIDIA drivers though, I will do a fresh install using the others and see if that changes anything.

System:
Desktop Computer
Motherboard: MSI PRO B550M-VC WIFI
CPU: CPU: AMD Ryzen 5 5600G (12) @ 4.46 GHz
GPU 1: AMD Radeon Vega Series / Radeon Vega Mobile Series [Integrated]
GPU 2: NVIDIA GeForce RTX 3070 Ti [Discrete]
Memory: 43.00 GiB
OS: CachyOS x86_64
Kernel: Linux 6.13.1-2-cachyos
DE: KDE Plasma 6.2.5
WM: KWin (Wayland)

You can use btop to show processes and see which one is consuming those resources. Sharing your system log upon the bug can also help. Thanks.

Thank you, that’s the kind of stuff I am constantly forgetting. Linux has a lot of tools and it’s hard for me to keep them all in my mind for when I need them.

I did a fresh install with integrated graphics disabled. I also used systemd-boot, as I figured the wiki-recommended path was the way to go in this instance. I’ve been stress testing it all day and it has worked perfectly so far. If it does happen again I will return with my logs to try to solve it.

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This has also been happening to me - & started recently. CPU ramps up to 110C & system kills itself to prevent it from overheating.

Also I haven’t caught anything that looks out of the ordinary on btop when it happens (besides the CPU usage & temp of course).

Operating System: CachyOS Linux
KDE Plasma Version: 6.3.0
KDE Frameworks Version: 6.10.0
Qt Version: 6.8.2
Kernel Version: 6.13.2-2-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X 8-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 6800 XT
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7C35
System Version: 2.0

Any recommendations, or directions to look into, would be much appreciated!

A log from sudo cachyos-bugreport.sh when the issue is happening could help, but I kinda doubt it. Does using linux-cachyos-lts fix this?

I have read in several places that it could be kernel level processes that are taking up CPU, but kworker and kthreadd do show up in btop, so if those aren’t topping the list it may be something else.
On a side note, there could be a CPU cooling issue. If there is a problem with the CPU fan (or water-cooling loop), the thermal paste is old or has improper coverage, or there are problems with overclock settings, these could lead to high temperatures.