mpv and use minimal CPU, instead using hardware acceleration (or not run whatever JavaScript. Firefox 38.0.5 consumes a lot of CPU on OS X 10.10.2 (Macbook Pro) CPU usage spikes when using Firefox Firefox CPU usage increases dramatically while playing YouTube videos full-screen Quick fixes if your Firefox slows down Firefox does not work - Common fixes to get you back up and running Firefox uses too much memory or CPU resources. It's a good practice to allow only original domain scripts for permanent (a choice ' allow') to have the web site you are visiting to display correctly all the useful information, but to keep side or extra domains only in ' forbid' or ' temporary allow' mode so the next FFox load will keep all these unwelcome scripts banned again. It runs natively using streamlink, and streamlink can use e.g. So keep NoScript installed on all your FFox'es and keep track on what domain you are actually allowing scripts from to be executed very carefully.

The simple (but not unique) solution would be to install NoScript plugin - causing immediate effect - Web Content process CPU consumtion will decrease almost to 0%. Those java-scripts are usually not origin of the web site you are working with but an ad based 3rd parties from somewhere else trying to collect some info from your FFox session or just to display switching ads on a side. The cause of the problem appears to be very simple: you may have too many tabs opened each having bulky and useless endless loops running java-scripts. This is a common problem causing nothing but the battery wasted energy decreasing unplugged operation time significantly.

Firefox taking up too much cpu