Question Different core clock readings across different installations of Windows

[RealJohnJohnson]

I had to reinstall Windows due to BSOD. Prior to the reinstallation, I noticed in MSI Afterburner that the core clock of my 7800xt read 2600MHz. It now only reads 2565MHz. As far as I can tell, neither of these numbers are correct anyway. The boost clock of the card is only 2475.

Does anyone know what is going on?

 

[Ralston18]

Margin of error?

How accurate + or - are those measurements?

All the more so if the numbers are not correct to begin with? Reason(s)?