rawfiul :
velocityg4 :
Just because you aren't doing anything. Doesn't mean the OS and other software aren't performing background tasks. Fluctuation is normal.
Each program polls the frequency and updates at set intervals. They can all be correct if they are polling at different times. Since each is taking a quick snapshot at different times.
Put the computer under a consistent heavy load to see if they all report the same frequency. OCCT is a great program for that and testing the performance of your cooling system.
but still fluctuating from extreme top and extreme bottom seems unjustified
That's just how Speedstep and other power saving features work. It doesn't affect performance. The CPU just ramps up to whatever speed is necessary for a task. Then drops back down to save power. This can happen many times per second.
https://software.intel.com/en-us/articles/power-management-states-p-states-c-states-and-package-c-states
https://www.intel.com/content/www/us/en/support/articles/000007073/processors.html
You can usually turn off Speedstep (EIST) and C-states in the BIOS. There isn't any real benefit to doing this. You'll just waste electricity and generate more heat.