speedtest.net upload speed capped at ~300mbit in Firefox
Categories
(Core :: Networking: HTTP, defect, P3)
Tracking
()
People
(Reporter: tom, Unassigned)
References
(Blocks 1 open bug)
Details
(Whiteboard: [necko-triaged])
Attachments
(1 file)
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169.43 KB,
image/png
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Details |
browsers.png
User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:82.0) Gecko/20100101 Firefox/82.0
Steps to reproduce:
- Go to speedtest.net on a connection with > 300mbit upload
- Run the speedtest
- Do the same thing in Chrome (and use the same server for a fair test)
I'm on Firefox 82 on Arch Linux and haven't tested to see if this is OS specific. I ran the test multiple times and each time, Firefox seems to cap the upload to ~300mbit after a second or so. It starts of in the 700s then slows down almost immediately (As you can see on the graph)
This website: https://cloudandfibre.co.uk/broadband-speed-test/ shows an even bigger discrepancy. Chrome gives ~700mbit upload while that site gives ~20mbit.
Fast.com also produces different results:
Chromium: 930mbit down / 680mbit up
Firefox: 620mbit down / 150mbit up
Actual results:
Chrome reports ~850mbit, Firefox reports ~300mbit and the speed fluctuates a lot.
Firefox fares less well than Chrome consistently, but upload is a lot worse than download.
Expected results:
speedtest should report the correct upload speed, not throttle the connection.
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Comment 1•5 years ago
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Bugbug thinks this bug should belong to this component, but please revert this change in case of error.
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Updated•5 years ago
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Updated•4 years ago
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Updated•4 years ago
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Comment 2•4 years ago
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FWIW I just tried this in release and I can't reproduce.
Same here, I recently got a gigabit connection. Every online speed test provider I tried, Firefox seems to be capped at 300 Mbps, where Chrome easily doubles or triples that. Internet speed tests in FF always result in around ~ 300 Mbps up and down.
This PC is directly connected to the router with 10 meter Cat5e UTP cable. Yesterday I tested Cat7 cable which improved the Chrome speed tests by ~ 100-200 Mbps, Firefox still maxed out at around 300 Mbps.
See screenshot here: https://imgur.com/a/YJdxPj3
FF 95.0.1
Ubuntu 21.10
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Comment 4•2 years ago
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In Firefox 115, we landed a large improvement to Http/2 upload speed (Bug 1596576).
If anyone who could reproduce this could re-test, it would be appreciated.
I'm experiencing a similar issue to this recently. Not sure if it needs a new bug report, but I'm getting 300-500 up/down in Firefox, and my full 2gig up/down in chrome and edge.
It works as expected on my Windows 11 machine connected to the same network switch and gets the full 2gig.
FF: 137.0.2
Windows 10 Pro 10.0.19045 Build 19045
Description
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