fps drops after about 30 min to 1 hour of gaming

[Spiralwind]

I have a laptop and it has a 980m graphics card.
when I play something like fortnight I get a good 120 to 180 fps and after about 30 mins to 1 hour my fps drops to a constant 40 fps and sometimes lower. to fix this I had to restart the game by exiting and reopening it and it goes back to normal for an hour and it happens all over again.
my temps are a constant 81 (max 92 ) while gaming but that was like that ever since I got this laptop and it worked fine before. My graphics card is also up to date, any help would be very appreciated

 

[iamlegend3490]

its probably thermal throttling done by your lap to prevent it from overheating . try using laptop coolingpads to keep the temp down .

 

[norcalsc]

Definitely throttling. The extended playtime is causing excessive heat build up, your performance is decreasing because your cpu is trying to keep the system from going into catastrophic meltdown

 

[Spiralwind]

but if that the case why haven't had this problem before

 

[Phaaze88]

Ever cleaned out the laptop since you got it? The interior does accumulate dust over time.

 

[Spiralwind]

i am unable to open my laptop but i have used compressed air
and i did this quite recently as well