Several of my PCs automatically updated to Firefox Quantum (FFQ) yesterday/Today. In my limited experience so far, most of them are working great. But my main PC is suffering from terrible "stalling" or "freezing" (but not hanging--it comes back) when using FFQ. For instance, as I type, a few characters at a time are displayed and then there is a massive delay before the rest of my typing is displayed. Similarly, while Web pages load fine, it is several seconds before I can scroll, and when I can, it happens in a stop-start manner. Worse, when FFQ is running on my PC, it also seems to cause other apps to stall, as well, albeit to a lesser extent.

I am running a freshly installed version of FFQ; uninstalling and reinstalling without add-ons did not help.