Rig not performing as it used to(i.e performance degraded badly in all games and benchmarks)

[CyborgRobot]

i have an

windows 10 pro

i5-3470

2x 4gb ddr3 ram

msi aero itx gtx 1060 3gb

everything worked fine for the past 2 years until now. I started noticing fps drops and less fps overall (almost 30% less). even in csgo i am getting only 120 fps and before i used to get double of that. I have checked my temps and they are usually below 70.

when i open my computer fps in games are bad but the game is playable but after one or two hours of gameplay, fps starts to decrease until i get 30-40 fps and at that point the game is unplayable(e.g. fortnite and r6s all the other games i have).

i did not felt to do any benchmarks before because pc used to fine but now i benchmarked it with cinebench and here is the result :     

is it good ??

[Jurrunio]

check temperature with HWinfo64, I reckon it's just thermal paste drying up, making things overheat

[CyborgRobot]

no i have reapplied the thermal paste 1 month ago

also tell me are my cinebench score good ?

Edited May 23, 2019 by CyborgRobot
forgot to add something