CPU/Processor help please!!

[darklegacy]

Hi, so i have recently ran into this problem that involves my CPU/Processor. My processor is a Intel Core i5-4210U CPU @ 1.70 GHz 2.40 GHz. So what happens is that sometimes my processor goes into this weird mode that makes the speed 1.66 GHz consistently. It never changes or improves its just 1.66 GHz. I use my laptop for gaming and its really frustrating because before I was getting 70-80 fps for League of Legends, and now i get 20 fps!! Please help me and thanks! (already tried restoring my comp to factory new)

 

[whoratesit]

If you can see lots of dust near the vents its probably overheating - if so, try vacuuming around the vents.