Is this a Windows 11 issue?

[Gabor Szots]

I have just discovered that my Stockfish benchmark has 3 times the value it used to have (that is, my PC is 3 times slower now). I think that might be put down to some latest update of the 24H2 upgrade. Following recommendations I found in the internet I tried to remove various Win11 patches (KB...) but to no avail.
Note: When no other programs are running the benchmark is OK but as soon as I start running new ones the bench soon becomes 2 then 3 times higher.

I'd be grateful if someone with similar experience could enlighten me what the cause may be and how to fix it. Possibly without having to do a clean Windows reinstall.

[Modern Times]

Coincidences do happen, so I wouldn't rule out a different cause.

[Gabor Szots]

Indeed, in safe mode all is well.