435417 - CPU usage grows to a very high level after Firefox 3 has been sitting idle

Status: RESOLVED INCOMPLETE

(Firefox :: General, defect)

Description

[Chris Wimlett]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9) Gecko/2008051206 Firefox/3.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9) Gecko/2008051206 Firefox/3.0

Since upgrading to Firefox 3 Release Candidate 1, on several occasions (and on two different PCs) CPU usage has suddenly increased to very high levels after Firefox has been sitting open but idle for 20 minutes or more.  Windows task manager showed that Firefox was using almost all of the CPU resource (up to 100% on one occasion).  Exiting Firefox didn't solve the problem, so I had to kill the Firefox.exe process from the task manager.  No problems if I'm actually using Firefox, and I didn't hit the problem with the beta versions

Reproducible: Couldn't Reproduce

Steps to Reproduce:
1.Open Firefox
2.Minimize
3.Wait 20 to 30 minutes
Actual Results:  
One some occasions, CPU usage suddenly starts increasing to very high levels - up to 100%

Expected Results:  
CPU usage stays at on near 0%

I usually have google mail open at the inbox (http://mail.google.com/mail/#inbox), but am not sure if I have on all the occasions I've hit the problem - it's happened with a single tab and multiple tabs open

Comment 1

[Nick Thomas [:nthomas] (UTC+12)]

Does the same thing happen in Firefox's safe mode ?
  http://support.mozilla.com/kb/Safe+Mode

Use "Continue in Safe Mode".

Comment 2

[Chris Wimlett]

I'll try it and report back

Comment 3

[uxorious]

Seeing the same thing here.
2 times today, I had FF running for a few hours with maybe 15 tabs open.
Both times when I came back to the PC, CPU was pegged at 50% (dual core PC, so all of 1 CPU).

Comment 4

[DBurton]

Same for me.

Did that with the last release of ver 2 also.

I see this on multiple computers all the time, though some with the same windows ver don't seem to do it at all.  

My PC's that seem to be doing it worst are AMD Athlon 64 3500+ CPU's.  My Intel E6550 Duo core machine hardly ever shows any CPU usage at all.

Win XP SP3, all fully updated.

Comment 5

[Wayne Mery (:wsmwk)]

using current v3.x ...
> Does the same thing happen in Firefox's safe mode ?
>   http://support.mozilla.com/kb/Safe+Mode

Comment 6

[Tyler Downer [He/Him]]

No reply, INCOMPLETE. Please retest with Firefox 3.6.x or later and a new profile (http://support.mozilla.com/kb/Managing+profiles). If you continue to see this issue with the newest firefox and a new profile, then please comment on this bug.