Hmmm, yeah, it could very well be a driver then, but I don’t know. One last thing to check: Open up the task manager, open up the performance tab, click the open resource monitor button. Open up the disk page, sort by “Total B/sec” and see if anything is using the hard drive like a virus scanner or other programs.
Also, what kind of temperatures were you getting up to on your CPU and GPU? It’s possible that you need to clean fans or check thermal pastes. You say it does it every second or so, and if it’s not something directly wrong with the project(bad loops, etc) or with the hard drive thrashing, that screams thermal throttling to me.
I just know that I’ve actually found 4.19 to have a massive increase in performance on this laptop and find it odd that you’re having problems with it.