Game freezes after ~20m of gameplay, doesn't change memory or CPU usage

I have a problem with my game freezing after about 20 minutes of playing. It does the classic “hl2.exe has stopped working” sort of crash where the currently playing sound(s) loop over and over while the game is frozen. The thing is that it gives no popup error message or sign of something stopped working, except when I open the task manager it seems to be using the exact same amount of memory and CPU constantly, with no fluctuations or differences like it does normally. There may be crash dumps in the file, I’ll take a look, but for now I would be grateful if there was a quick fix.

P.S. This only started happening recently, within the past month. Before this started, I attempted to overclock my PC, but decided to revert it back to normal. This may have something to do with it, and I will take a look at my settings again. Before, I could go 4+ hours with no problems whatsoever.

Edit - Checked crash dumps, the only ones were from more than 3 months ago; checked my overclock settings and everything is default.

Edit2 - My computer is definitely qualified enough to run gmod. In fact, it’s probably overqualified, tbh, hence the removal of overclock settings. I have an intel 3770k 8 core and an NVidia gtx 680 with 16gb of RAM.

Edit3 - Sorry for all the edits, but I just would like to add that the same thing happens on TF2 as well, if that helps.