Question games running at incredibly low fps in any mode other than windowed bordered

[sn0wbit_]

at random points in time, specific games that normally run fine in fullscreen start running at like 10 fps and below. i have an rx 480 4 gb, an i5-6402p, and all of my drivers are updated.

edit:
games i know of that this happens to are diabotical, roblox, tf2, and csgo.
other games probably have the same problem i just haven't experienced them yet

 

[SteveRX4]

Is this a laptop? Make and model? Age?

Otherwise - PC Spec? including monitor?

 

[sn0wbit_]

desktop. important specs in original post. and a 144hz monitor. i dont think its a hardware issue because this only started happening this year and ive had this pc since 2016.

 

[SteveRX4]

rx 480 4 gb, an i5-6402p
case?, ram?, PSU? motherboard?
OS? Monitor?