A few other things you could investigate:
Run Activity Monitor > Window > CPU History
This will show number of logical cores
Run Intel Power Gadget
The Intel® Power Gadget project is no longer active.
www.intel.com
In Terminal run this command (all one string), if you have 10 logical cores:
yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &
If you have hyperthreading and have 20 logical cores, run this instead:
yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &
This will fully load all logical cores of the CPU.
Observe power, frequency and utilization in Intel Power Gadget. If any drop significantly below the spec for your machine it means it is throttling and you may have a cooling problem. For example, the frequency should be near 3GHz, or maybe turbo boosted as much as 4.5Ghz
Close terminal to terminate the yes command. Or kill the "yes" processes; or shut down.
