1153605 - lagging response, high cpu usage, windows 7, FF36 vs FF37

Status: UNCONFIRMED

(Firefox :: General, defect)

Description

[Claude]

Attachment: all.png

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:36.0) Gecko/20100101 Firefox/36.0
Build ID: 20150222232811

Steps to reproduce:

Nothing specific. Generally higher cpu usage resulting in a lagging response.

As test reference: 
1 tab, page https://support.mozilla.org/en-US/kb/install-older-version-of-firefox, mouse wheel scroll up-down once per second, CPU graphs from ProcessExplorer v14.06.

Tested in host OS, windows 7sp1, FF35 vs FF36 vs FF37 (installed back and forth).

Tested in VirtualBox guest OS, windows 7sp1, FF36 vs FF37 (installed back and forth), FF standard installations, no plugins and no extensions.

Laptop, i7, 8GB, SSD. CPU @ normal speed 2.2MHz, plenty free memory available.



Actual results:

FF37 uses CPU twice as much as previous FF35 and FF36

Installed back and forth FF36 and FF37, in host OS or in vm guest OS. Always same results.

The page scrolling test, with CPU graphs, is just a demonstration of the issue I encounter with FF37 no matter the site I'm browsing.  I develop PHP, test on various browsers, and when testing with FF37 I can hear the CPU fan running higher, and feel the slowness of FF37.


Expected results:

CPU use should stay similar.

Comment 1

[Claude]

Tests were made with FF stable releases.