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Max CPU usage after leaving browser idle for 30minutes+




10 years ago
9 years ago


(Reporter: Scott Moxham, Unassigned)



3.0 Branch
Windows Vista

Firefox Tracking Flags

(Not tracked)




10 years ago
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9) Gecko/2008051206 Firefox/3.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9) Gecko/2008051206 Firefox/3.0

I have noticed that if I leave a few windows open (2-4, not huge numbers), opened using Ctrl+N, my whole system will start to behave slugishly. Checking the task manager the culprit was Firefox. Memory usage was normal but CPU usage was maxing out. Closing windows one at a time it is only ever one window that makes a difference.

The sites I have noticed it on are websites internal to my company (i.e. not public) that I have written personally. They have no AJAX / refreshing of any kind, there is no javascript apart from a few onclicks that simply perform set the css property display to none/block and nothing more complex, i.e. nothing that would use CPU cycles. No plugins used. Pages all use quirks mode but just basic HTML / CSS with limited javascript.

Reproducible: Sometimes

Steps to Reproduce:
1.Open Firefox
2.Open 2-3 new windows using Ctrl+N and open a web page in each
3.I was refreshing the pages every couple of minutes (with refresh button or F5 key) but not navigating to other places. Using other applications on same computer in between.
4.Continued to work in other applications but not touching Firefox at all for 30 minutes or so.
Actual Results:  
Computer became slugish due to Firefox maxing CPU. Seemed to be a single window causing the problem. Closing the window solves the problem without closing the rest (although no indication as to which, just have to close one at a time until CPU usage drops).

Expected Results:  
No reason for Firefox to be using any CPU. It was not being used.

I'm running Vista Ultimate SP1 on Pentium M 2.13GHz, 2GB RAM (aprox. 750MB free), GeForce Go 6800 Ultra, running Aero interface. Only plugin I have installed is Glasser.


10 years ago
Version: unspecified → 3.0 Branch

Comment 1

10 years ago
If this is a brand new profile (a few days old at the most), it could be the urlclassifier2.sqlite file (spyware/malware database) that is being downloaded. If I remember correctly, it starts 30 minutes after you start the application. The whole database is currently 55 MB large, but it should be downloaded in a few days, and then the download will stop.

Your symptoms look like Firefox 3.0 beta 5, but the current release candidate is supposed to be a lot better.

Comment 2

10 years ago
I am running Firefox 3.0rc1

Comment 3

9 years ago
do you see this problem with current 3.0 release and 3.1 beta?
Keywords: perf

Comment 4

9 years ago
Sorry, I had forgotten about this bug and it doesn't seem to happen any more. I can't be sure, which version it was fixed in but I haven't seen it for quite a long time, I am only using 3.0 and haven't used the 3.1 beta yet.
Last Resolved: 9 years ago
Resolution: --- → FIXED

Comment 5

9 years ago
Wrong status
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