have you experienced any crashes,restarts,or pure shutdowns?
You can use task manager to see your cpu usage.MSI AFTERBURNER is also a good option,but only works while gaming and its more complicated to set up.
What has led to your concern that your cpu is not working right?
Most basic way is to view the usage in task manager. Right click on the taskbar at the bottom of your screen > click the 'task manager' option > click on the 'performance' tab > and it should be the CPU section that defaults to your view. There you can see all the cores/threads being used and at % utilization and clock speeds (GHz). Try running a few benchmarks like Cinebench r20 or r15 to see if your CPU is being utilized 100% to it's marketed clock speeds. Due note that the clock speeds will drop the hotter the CPU gets to prevent long term damage.
Normally if you are not experiencing any crashes or stutters your CPU should be outputting it's stock performance. If you have the kind of unlocked CPU like AMD Ryzen or intel's K series chips then you can push the performance even further with a little research.