I have a 9900k, latest windows version + updates and disabled spectre/meltdown via Inspectre. I disabled every Cstate powersaving core parking standby etc. Overclocked using static voltage and frequency nothing dynamic. At every reboot for about 10 min everything is fine on every benchmark (cpuz/cinebench etc). Give it 10 ish minutes and then everything gets lower by about 5%. I checked my event manager nothing happens when it gets slower. Anyone experienced the same?