6800k drops OC

[Gwyno]

So there is a bit of an issue with my cpu. I've used to run my 6800k @4.2ghz (1.225v) but few days ago (after last windows update) I've noticed a bit of a drop of fps; after quick stress test it turned out that all bios settings were brought back to default (3.6ghz cpu, 2133mhz ram, even fancurves). So i tweaked all setting to the point at which they were beforehand but... in windows I'm still running my cpu @3.6ghz (which is stock). So I turned down multiplier a bit (to 4.1ghz) and turned up voltage (to 1.245v)... and in HWM I'm running at 3.4ghz while in stresstest. The hell is happening? 

Specs:

6800k
x99a sli plus
dark rock 3
spc supremo 550w 80g+

2x8gb 3000mhz

[Nocte]

Did you update your BIOS? Windows update does not have anything to do with BIOS and clock speeds.

 

Anyhow, update BIOS (or reflash it) and try to re-apply the overclock.

[Gwyno]

15 minutes ago, Nocte said:

Did you update your BIOS? Windows update does not have anything to do with BIOS and clock speeds.

 

Anyhow, update BIOS (or reflash it) and try to re-apply the overclock.

BIOS is updated but I'm bit of afraid of reflashing it (frequent powerlosses in my city)