Hello
In addition to TaskManager and Process Explorer, there are several tools that can help you check for threads that are causing high CPU usage.
One such tool is ProcDump, which can be used to take memory dumps during CPU spikes. Then you can inspect the call stacks of all threads.
https://learn.microsoft.com/en-us/sysinternals/downloads/procdump
Another tool you can use is perfmon, which allows you to monitor your system's performance and keep checking for threads that are hogging the most CPU.
https://www.digitalcitizen.life/basics-about-working-performance-monitor/
Of course, if it is outside of working hours and the server can be restarted, you can also try to collect user mode dumps to analyze the root cause.
https://learn.microsoft.com/en-us/windows/win32/wer/collecting-user-mode-dumps
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