For some time now, I have noticed my laptop acting sluggish compared to when this was still brand new and after tinkering around with sensors, I found out that my laptop is thermal throttling. Tried changing the thermal paste and cleaning the fan but it does not work my CPU is still hitting around 80 to 95 and hits 100 when the GPU is active. My laptop is an ASUS X456U with a Core i5-6200U and GeForce GT940MX.
Have you tried undervolting using throttlestop? If you previously used intel XTU perform a clean uninstallation of the xtu and use throttlestop. For some reason xtu gives me thermal throttling before even when temps are good. Make sure to keep your vents clear by lifting the laptop up with something
And I saw 1 interesting video on youtube bcs i had problems with temps on my pc and that guy has a laptop. He went in power options and changed proccesor maximum active state to 99% so that it disable cpu boost and it helped him I will link video https/youtu.be/wX-yHV6SIFU maybe you give this a try! Hope it helps