Hello,

Try Firefox Safe Mode to see if the problem goes away. Firefox Safe Mode is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes).

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu:

• Click the menu button , click Help and select Restart with Add-ons Disabled.

If Firefox is not running, you can start Firefox in Safe Mode as follows:

• On Windows: Hold the Shift key when you open the Firefox desktop or Start menu shortcut.
• On Mac: Hold the option key while starting Firefox.
• On Linux: Quit Firefox, go to your Terminal and run firefox -safe-mode
  (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)

When the Firefox Safe Mode window appears, select "Start in Safe Mode".

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, theme, or hardware acceleration. Please follow the steps in the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article to find the cause.

To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help others with the same problem.

I once tried doing this, but as it takes some time for that thing to take effect (I mean it will be noticeable like after two days), it's quite troublesome... And at the same time without hardware acceleration scrolling itself becomes a bit less smooth, so it will be harder to notice the effect. I'll try it once more.

Sorry for the late reply...

Tested it by running in safe mode for like 5 days (approx.) . Unfortunately in safe mode it's way harder to notice the difference, as without the hw acceleration (and it seems that not only this is disabled) browser performance drops. But still after some time the responsiveness dropped - like scrolling tab bar became a bit choppy and scrolling pages became less smooth.

Is there anything else I can try / test?

--- Currently I'm trying to get rid of some of the opened tabs and move some of them to bookmarks. But I'm not sure this will help, as the same thing happened before, when I had less tabs.

Try using bookmarks to save pages you want to revisit instead of keeping them in tabs. That way, you will not need to have so many tabs open.

On one hand yes, but on the other hand 95% of them are not loaded anyway. Do you think my issue can be linked to the amount of unloaded tabs?

I don't have a solution but I'll add an observation. When I notice Firefox becoming sluggish, or occasionally and painfully turning the entire tab content area black, I check the Task Manager and usually see that Firefox is above 2.5 GB of memory. For me, that is around where I need to File > Exit and start it up again; there's just no point in waiting for things to come back to normal at that point. The time required to hit 2.5 GB varies, presumably based on the content I've viewed, but I probably hit it a few times per week if I'm not intentionally restarting Firefox for some reason.

There might be tools to monitor for high memory usage and either warn me or take action, but I haven't researched them. So far, restoring the session (20+ windows with an untold number of tabs) has been reliable (knock on wood) so while this imposes a kitchen break on me, I consider it a tolerable price to pay from time to time.

Do you mean that you leave the browser running for days on end? Maybe that is part of the problem. Things are likely to get more sluggish as the cache fills up.

jscher2000 Didn't measure this actually. But in most cases it's not more than 1.5-2 Gb.

finitarry Yeap, as it's running on a notebook which technically never shuts down, Firefox keeps on running as well. Shouldn't it be intelligent enough to manage cache automatically? Or what exactly do you mean?

If I am not going to use the browser for a while, I close it. At the end of a browsing session, I clear everything but cookies (and permission exceptions, but I took that out of the list). That way, I start again with lots of room for everything. I allow only a few sites to set cookies, so there are not a lot of those.

finitarry said

If I am not going to use the browser for a while, I close it. At the end of a browsing session, I clear everything but cookies (and permission exceptions, but I took that out of the list). That way, I start again with lots of room for everything. I allow only a few sites to set cookies, so there are not a lot of those.

You do understand, that you are exceptional here? =) I use FF daily almost all of the time, so I almost never close it.

Unfo, none of my friends can test this, as they use desktops and just switch em off every time.

And... Just a question - is Intel card more than enough to support HW accel for Firefox? As on my desktop Firefox runs more smooth, than on my notebook (my desktop has Radeon HD 6950 and Intel i5 CPU).

I really cannot tell you that. I use Mac OS.