Hi, did you manage to solve your problem ? I believe to have the same issue. Latencynom is pointing to kernel, and it's getting worse over time.
I tried clean installation of windows, but the same issue. It appears even on idle, like when I'm moving window around. The same on my second boot Linux. And I know how that sounds, but I have a feeling like I can see the same behavior in bios. I tried like 3 or 4 bios versions. I tested RAM like 3 times, no errors. I bought new PSU since last had like 7 y.o. but the same result. Temps look good, so I can't believe in throttling. The only left parts are cpu and mobo. But I can't know which to RMA and I don't want to wait for RMA if I can solve it myself somehow.
I tried to look at latencytop but didn't know how to interpret the data. EXPO changes nothing like other bios options.
I didn't play with any vlotage or frequency. Mostly default values in bios.
Have somone any idea ?
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hwinfo report