Low speed in Firefox

[ajavibp]

Hello, lately I have noticed a lack of speed in firefox and I have found something curious. The same speed test gives me half the speed in firefox than in chromium. I have moved the user folder to start a clean session, but with the same result. I downloaded an ISO from Ubuntu with wget and the real speed is the one that marks chromium.Someone else happens?Firefox v 77.0-1 from the debian repository.
Thanks!

[dibl]

That's such an odd problem, I repeated your experiment to see how they behave here. I have the same Firefox ver. 77, and I use SRWare Iron ver. 81.0.4200.0. Here are the results:

FF                                               Iron

Down -- 52.07                             Down -- 54.59
Up      -- 11.78                              Up     -- 11.98

[ajavibp]

Thanks for your answer. I will have to continue checking, the bad thing is that I do not know very well what to check.

[dibl]

You might want to study the dependencies of Firefox, and see whether there is reason to be suspicious about one of them.  Or, maybe remove/purge Firefox and all of its dependencies, rename the user config files related to Firefox, and try a new installation.

If you have access to a second hardware system on the same router, it would also be interesting to know whether Firefox is a problem on that one also.  Even if it were a windows system, you could boot a Linux live USB stick with Firefox on it, and test it that way.

If you are using a laptop, it might be interesting to go find an open wifi spot and try through a different router.

Just some ideas for you.

[ajavibp]

I'll try. Thanks!

[axt]

That's such an odd problem

More likely an add-on problem.

remove/purge Firefox (...) and try a new installation

And I thought we were here at Linux.

rename the user config files related to Firefox

Now, that's a useful hint.

ajavibp, close firefox and execute:

Code Select Expand

$ mv ~/.mozilla{,_old}

[dibl]

More likely an add-on problem.

Yes, good chance.  Find out for sure by reinstalling bare Firefox.   

[axt]

Find out for sure by reinstalling bare Firefox.

Don't take it amiss, but this is nonsense! Re-installing Firefox doesn't help at all.

Add-ons and user configurations are stored in the profile directory. So you rename it (as set forth).

[eriefisher]

Rather than starting fresh I would disable any addons. If you get a desirable result then re-enable one at a time to narrow down. If with all the addons disabled you still have a speed issue then I would rename the ~/.Mozilla directory for a fresh start and test the speed. You haven't enabled an unecessary proxy by chance?

[ajavibp]

I have removed firefox and moved user folder. I have reinstalled, and nothing, everything the same. I have tried to install firefox-esr (an older version), and nothing changes either.

I am going to test with another PC in which I only have windows, and with a USB-live, to see what happens.The speed difference is brutal, 250 Mbps with firefox and almost 600 Mbps with Chromium.
Thank you very much to everyone for your help.

[eriefisher]

Just for curiosity, using speedtest.net.
firefox:  Installed: 77.0-1     ping-15  down-27.77  up-4.86
google-chrome-stable:  Installed: 83.0.4103.106-1     ping-15  down-27.78  up-4.18
Results: Looks near identical to me. One thing though Chrome doesn't render the website correctly. Oh and these are tested using the same servers.

[ajavibp]

I'm using speedtest.net too (with the same server).On another PC with windows, everything is normal. I have checked the router and I don't see anything strange, QoS is disabled and there are no active priorities or anything like that.wget is fine, I downloaded at 72 MB / s, so it doesn't seem like anything from the system, but rather just from firefox.

[ajavibp]

This really was not expecting it.
I have started a Xubuntu 18.04 live via USB. Without touching anything just start:
Firefox 72.0.2 -> Download 251 Mbps, Upload 262 Mbps.
Chromium 83 -> Download 603 Mbps, Upload 626 Mbps
After updating Firefox by repositories:
Firefox 77.0.1 -> Download 274 Mbps, Upload 272 Mbps.

[ajavibp]

Thinking it might be a bug on Firefox I just saw this: https://bugzilla.mozilla.org/show_bug.cgi?id=1636904
At least I stay calmer, I was going crazy,

[dibl]

Aha!  Good find -- that is good to know.