Lag every few second

Probably seen this topic before but my game keeps dipping down from 60fps to around 20fps every few second and can stay like that for quite a bit. I dont know if this is a heating issue or just the computer doing computer things this has also happened on GTA 5 but is worse on MCC ever since a Windows update it has f*cked my computer because people are gonna ask I have a Dell Inspirion 7567 (2017) with 1050ti i7700HQ 16gbs ram and MCC is stored on my SSD and im connected to a 1080p 75hz monitor.
Halo Reach is not hard to run ive tried using performance settings turned on/off vsync and even turned off freesync on my monitor but to no avail. thank you for the help.