I am running 2019.3 on a windows 10 laptop.
I was jumping around in some Firefox pages and had been doing so for about 30 minutes or so. I went through a lot of pages.
After a while my system suddenly became very sluggish and then almost locked up. It also started blowing more hot air than usual and I had to power down and reboot to get it to straighten up. It is running cool again and no sluggishness.
-- Dan Beaver (KA4DAN)