User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1 Build ID: 20111220165912 Steps to reproduce: We've tried to show on mouse hover previews of items listed in tables (graphic files preview). Actual results: We've encountered strange slowdowns on Firefox 9.0.1. After some time we've found out, that it is caused by borders. Later we've read about similar problem on bugzilla (bug 454203). It seems that floats also may be problematic for Firefox. Link to the code with test could be found here: https://gist.github.com/1578087 "Hints"/"Popups" (absolutely positioned spans) showing under mouse cursor slow down a lot on Firefox. Just add few columns, enable borders and/or float and watch Firefox crawl :(. Expected results: Firefox should behave here like Chrome, Opera and IE 9 - smooth and without slowdown.
WFM on Mozilla/5.0 (Windows NT 5.1; rv:13.0a1) Gecko/20120212 Firefox/13.0a1 ID:20120212031149 I tried various combinations of the options at the top, including all and none selected and could not reproduce. Does the issue still occur if you start Firefox in Safe Mode? http://support.mozilla.com/en-US/kb/Safe+Mode How about with a new, empty profile? http://support.mozilla.com/en-US/kb/Basic%20Troubleshooting#w_8-make-a-new-profile Can you capture the contents of about:memory when you experience the performance issue?
Here is some results of my investigation: - Safe Mode - Everything is OK - no slowdown, - Normal mode but all add-ons disables - I still have slowdown, - Normal mode - I still have slowdown, - Empty profile - I still have slowdown.
That sounds like HWA is causing you issues. Please post the contents of the graphics section from about:suppport
Informations from about:support Grafika Opis adaptera Intel(R) HD Graphics Family ID dostawcy 8086 ID urządzenia 0126 RAM adaptera Unknown Sterowniki adaptera igdumd64 igd10umd64 igd10umd64 igdumdx32 igd10umd32 igd10umd32 Wersja sterownika 188.8.131.528 Data sterownika 6-10-2011 Opis adaptera (GPU #2) NVIDIA NVS 4200M ID dostawcy (GPU #2) 10de ID urządzenia (GPU #2) 1056 RAM adaptera (GPU #2) 512 Sterowniki adaptera (GPU #2) nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um Wersja sterownika (GPU #2) 184.108.40.20683 Data sterownika (GPU #2) 6-5-2011 Właczone Direct2D true Właczone DirectWrite true (6.1.7601.17563) Parametry ClearType Not found parameters of ClearType Renderer WebGL Blocked for installed graphic card - problems with drivers. Okna ze sprzętowym przyspieszeniem grafiki 1/1 Direct3D 10
Please disable HWA, restart Firefox, and see if that solves the speed issue. Tools -> Options -> Advanced -> General -> Uncheck 'Use hardware acceleration when available' and restart
You are right - problem disappeared after disabling HWA.
Component: Untriaged → Graphics
Product: Firefox → Core
QA Contact: untriaged → thebes
Summary: Firefox slowdown on borders and floats → [HWA] Firefox slowdown on borders and floats
You need to log in before you can comment on or make changes to this bug.