No matter what I do, the cpu refuses to boost from 1.9ghz to 2.8ghz. In fact it hasn't even reached 1.9ghz for some reason. I've put the processor under heavy load for about 30 minutes and the processor only got to 1.8ghz at most with a core temp of about 30 degrees Celsius. So overheating has been ruled out. It seems that the cpu's multiplier has somehow changed from 28 to 18 in amd overdrive. The clock can only be modified in amd overdrive and not in the bios on my laptop. So does anyone know how to set it back to 28?
Check your power plan as it is shown on video How to Use maximum CPU power in Windows 10 - YouTube
But leave minimum processor state on defaults settings.
Try to reset all settings in AMD overdrive and switch turbo core on/off for experiment.