Question Laptop sometimes fast sometimes slow

[a guy with a weird issue]

My laptop most of the time runs games like GTA SA at 10-15 fps but sometimes very rarely runs them at 60 fps here is my specs
Ram 4gb
CPU Intel i3 m350 2.27ghz
Graphics Intel hd
Operating system windows 7

 

[Grobe]

Probably it get hot and throttles the CPU <relevant search result answer on how to test this>