Question Help with laptop's games performance

Sep 24, 2020
Sorry if this is the wrong section to post but I assume I'm in the right place.
my laptop is dell latitude e6540 core i7-4810MQ cpu @2.8ghz 2.8
ram : 8 gb
gpu : amd radeon hd 8790m 2gb

So before I had no problems with gaming at all playing fortnite at 60 fps or apex somewhere between 40-60 and everything was fine, until recently I noticed that my laptop processor falls down in these games, instead of 2.8 ghz or even turbo above 3 it goes down until it gets stuck at .79 ghz, only on those two games, while on valorant the lap works just fine, it is not an overheating issue because I had fortnite making my laptop above 90 c degrees and nothing happened then, now above 80 and the game starts to stutter and fps goes down, I changed the thermal paste, fans sound seems fine and working, laptop is fine in everything except apex or fortnite or anything of their sort like pubg lite, help pls :(