EDIT: problem seems to have disappeared after rebooting.
Opening a new tab in Chrome or switching tabs in Task Manager takes multiple seconds. Even simple actions like editing this question have noticeable lag at times.
CPU usage is hovering at 20-30%; RAM is 35% used (with 40GB available total).
CPU is an 8th-gen i5; GPU is a GeForce MX250.
More detail: Switching back to the Processes tab in Task Manager: it just took 12 seconds to populate and start its refresh cycle. When I switch back to Performance, that takes 2-3 seconds. Alt-Tabbing between apps is slow enough that if I start typing right away after performing the key combo, it misses the first word or so. Opening a new tab in Chrome takes about 3 seconds.
Overall it feels like the system is swapping to disk, but there is no reason why it should be doing so.
I notice that the "Power usage" column in Task Manager for Chrome often shows High even when neither CPU nor GPU utilization is above 10%.
I do have a few bazillion Chrome tabs open, though the large majority of them are suspended (using The Great Suspender extension) and don't consume resources.
I just switched back to Windows recently after many years under Linux and OSX so I'm not really up to speed on the best way to troubleshoot something like this.
Some screenshots:
Update:
I remembered that earlier I had the laptop running in a sleeve with the lid down for an hour or so (due to thinking it was suspended when it wasn't). I didn't notice anything amiss when using it afterwards but perhaps it's possible that this caused the fan to overheat and burn out.


