Since basic troubleshooting like restarting, clearing cache, and disabling extensions hasn’t helped, I’m wondering if this could be related to hardware acceleration, content process limits, or a corrupted profile after the recent Mozilla Firefox update on Windows 10. The lag and freezing with just 5–10 tabs open is noticeably different from the smooth performance I had before.

I regularly work with multiple tabs while managing smokeycloudz.com, so this change has significantly disrupted my workflow. Any advanced suggestions would be greatly appreciated.

I have a similar problem, since an update maybe a month or two ago, and I'm on a Mac (M3 MacBook Pro running the latest version of MacOS 15 Sequoia (15.7.5). I was previously able to have dozens of tabs open across multiple windows with no problem. Now 3 open windows running a total of 5 tabs is enough to get the spinning beach ball repeatedly when I switch to Firefox, switch windows, copy the URL bar, etc.

Clearing browser cache, restarting Firefox, rebooting my Mac, and Firefox updates since then have not fixed the problem.

Problems are worst if one or especially multiple tabs play video or audio -- e.g. multiple YouTube video pages open on tabs (even if none of these tabs are active or foremost on a window) and/or Pandora music player, If Pandora is playing while I work in Finder or another app, then I switch to Firefox, the Pandora page has not kept itself updated, and clicking it to update the content triggers the spinning beach ball, as does ⌘-N to open a new window. If Pandora is closed but I have more than 2–4 YouTube tabs open (even if no video is playing and none of the tabs is in the foreground in its window), I also get spinning beach ball.

All of this makes me suspect there might be a problem with how a recent Firefox update handles its media players, so something is now active in the background of EVERY tab that wasn't active before.