I have disabled Meltdown and Spectre security mitigations, because I do
not run untrusted non-free software and performance is higher.
=> Meltdown
=> Spectre

Simultaneous multithreading (HyperThreading) is also disabled, because
it is often buggy, can be security issue and in many cases hurts performance.

Overclocking (TurboBoost) is also disabled, because it forces hardware
to work out of nominal regular work regimes. Also it could be used for
effective side-channel attacks.
=> https://timing.attacks.cr.yp.to/overclocking.html
=> http://blog.cr.yp.to/20230609-turboboost.html