Firefox unbelievably laggy on dell laptop

Question

I own a Dell XPS 15 (2014 model), running windows 8.1, where firefox has always been slow and sluggish. I haven't been able to solve the issue through google.

One of the problems is that scrolling is laggy. The scroll motion happens about 0.5~1 second after I move my fingers.

Secondly, youtube videos on full screen are a no no. Any resolution is just sluggish. Even worse, when I move my mouse over the video frame (on any html5 or flash player) the video goes from 30fps to 1spf (Second per frame). This is on non-fullscreen.

Even if I put my laptop on high performance with everything maxed out I still can't get firefox to function normally.

Chrome on the other hand works like a charm.

Any ideas?

Note: please don't give me answers like "use chrome instead".

Answer 1

there are several things you should do. Start firefox in safe mode and look if the problems are remaining. If so:

1. Update mozilla
2. Update your graphics driver
3. Check if you have the latest plugins installed: https://www.mozilla.org/de/plugincheck/
4. View your settings and check if things like Hardware acceleration are ticked.

If that also dind't help check in type in the url about:config and search for

layers.offmainthreadcomposition.enabled

If the value is true change it to false. Restart your browser and test if it worked.