@rakshasa12 Exit HWiNFO when testing with ThrottleStop so it does not interfere with your results. Press the Limits button and open up the Limit Reasons window. Look for any red boxes which indicates the reason for throttling.
I am 99% sure that you will see BD PROCHOT glowing red under the CORE column. This is a very common problem, mostly on laptops but it also happens on desktop computers too. It is common for MSI desktop boards. If you see this box in red, clear the BD PROCHOT box on the main screen of ThrottleStop.
Does your CPU return to its normal speed after doing this? Post some ThrottleStop screenshots and I will try to explain what is going on.
Edit - The Task Manager Performance tab does not show CPU usage. It shows CPU utilization. These are two different things. If you look at the Details tab, that should show CPU usage at 100%. The CPU is working hard but at a very low speed so it is not accomplishing too much.