Firefox 43.0.4 on Ubuntu 15.10 incredibly slow to load pages

Question

Since a few days now, I think since the last Firefox update, but I can't be sure, because I've been away for a few weeks until Jan, 10th, Firefox is practically not usable any more. It takes forever to load a page (more than a minute) and most of the times doesn't even complete.

I am sure the connection works (it's a fast 1Gbit/s point-to-point fiber with the ISP) because when I use Chrome or Opera, they're flashy fast.

I also believe it can't be the profile/user, since I've also tried creating a new user in Ubuntu. Same effect: Chrome super-fast, Firefox doesn't practically work.

Then, on the same laptop (Lenovo S540) I have Win10 in dual boot, and Firefox 43.0.4 as well in it. So, the thing is that in Win it works perfectly fine, so I guess the problem comes only for the Firefox in Ubuntu.

To further rule out a connection issue (a part from trying both with wifi and eth connection), I've brought the laptop all the way to my office and tried with the connection at work. Well, exactly same thing: Chrome snappy. Firefox unusable.

Am I the only one having this issue?? It's a few days I'm looking online, but I haven't found anybody else's post anywhere about this...

I'm an almost-expert (not professional, but 10+ years of exp) user in Linux and Firefox both, but I really can't understand what's going on here... Is anybody having a hint for me about where to look at next?

Solution 1

In the end, after an update to Firefox 44 everything works again, more or less... I don't know if it's really solved, since it's still notably slower than Chrome, but at least is usable. A few days ago I tried the nightly (ver 46) and it had the same problem, so I already started despairing that an update wouldn't solve... But actually it did, so I'm happy. But still curious about what happened...

Solution 2

I had a similar problem. Disabling Ubuntu Modifications add-on solved it. According to these answers, it is the interaction of adblock plus and the Ubuntu Modifications add-on.

• Firefox very slow [closed]
• Mozilla Firefox terribly slow on Ubuntu 14.04

Comments

[mikewhatever]

Don't know what an expert should do (experts should know better), but for a regular non-expert user, I'd advise trying a new Firefox profile.

[Admin]

Other simple things to try: Safe Mode, Reset addons and settings, reinstall Firefox via package manager.

[Bill]

@mikewhatever As I said above, I've not only tried a new profile, I've also tried creating a fresh Ubuntu user ('virgin' home directory and all...), with the same effect. By saying I'm not beginner, I mean exactly that all the 'standard' attempt have been tried... I'm really trying to figure out why I haven't find anybody else around with a similar problem...

[Bill]

@clearkimura I tried the Firefox Refresh procedure... Still have to try reinstalling... but I am a bit in doubt for that, since Firefox it is such a big (and default) part of Ubuntu...

[bain]

Are there any errors in dmesg or syslog? If you run Firefox from the command line are there any errors? Any errors in ~/.xsession-errors? Does top show anything unusual? To dump stack and see what Firefox is doing while hung try cat /proc/$(pidof firefox)/stack

[Bill]

Thanks, I'll try disabling Ubuntu Modifications, but actually I don't have any adblock nor any other add-on... especially after the Firefox Refresh procedure ;-) But I'll see if by chance it works...

[Tim]

I have same problems as the answer author. Tryed this solution - it doesn't helped me.

[Chris]

this seems to work for me with ublock origin too

[Pablo Bianchi]

Sad but true. Couldn't find related bug report on Launchpad.