Ubuntu Mate 22.04. all updates applied
uname -a
Linux WZ-M18xR2 5.19.0-42-generic #43~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Fri Apr 21 16:51:08 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
nVidia GT 675M (mobile) with driver 390.157 (latest supported. running for several years)
Very recently the system has gone from being able play FHD youtube video at 60FPS with no dropped frames to 360p with 50% frames dropped.
Also stellarium has dropped from a constant 60FPS to 6-7 fps. I can see in the nVidia settings panel that the card is working and GPU usage increases with application use.
htop shows no excess load and reasonable CPU utilization for these apps so what else might be going on?
The only other issue I had was firefox (snap) was constantly freezing the system so I removed it and installed the package version from the app dev site. This solved the crashing but I haven't been able to pinpoint the performance issue.
Any suggestions welcome.