Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Lately, Firefox has been running up CPU usage, usually taking up at least 25% CPU usage. Not a problem since I'm on a quad-core, but that measurement is spread across all CPU's, so it is still using up the equivalent of an entire core, and pushing up my system's heat output.

Is there any way I can track down what part of firefox is using up so much CPU?

share|improve this question

migrated from Feb 15 '13 at 11:31

This question came from our site for professional and enthusiast programmers.

When you say "what part" what do you mean? Are you asking whether it's the rendering subsystem, or the network processing subsystem, etc.? If so, does it really matter? Firefox just uses a lot of CPU cycles on your machine, so either switch to another browser or upgrade your heat dissipation solution. – Lokerim Feb 15 '13 at 4:39
I want to know whether it is a website, addon, or runaway script. As well, switching to another browser (chrome is the only other worthwhile alternative) is a trade-off: I get lower CPU usage with chrome, but higher memory usage and a MUCH higher rate of crashes. And upgrading my system's heat dissipation is impractical because I can't afford hardware upgrades right now. – Zauber Paracelsus Feb 15 '13 at 4:46
I'm seeing the same thing on my system. FF just spontaneously takes up 100% CPU for some time. then stops. then starts... I'm not sure what it's doing. PS. This is a question better suited for superuser. – Keith Feb 15 '13 at 4:53
up vote 2 down vote accepted

Some thoughts

  1. There isn't a firefox task manager so no view there (like Chrome), but they are working on it
  2. Secondly have you upgraded to the latest version of Firefox or looked at prior versions for the same kind of behaviour
  3. There is also the Firefox CPU Over-utilization Guide to aid in these kinds of issues
  4. You can check for possible issues with memory which may indicate CPU problems in the lower levels of Firefox about:memory
  5. Another person with similar problem on StackOverflow | As well on SuperUser
  6. You might also find some extra-info using Process Explorer for Linux
share|improve this answer
Thanks, this should help me track it down. – Zauber Paracelsus Feb 15 '13 at 8:31

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .