2007827 - Slow upload speed in Firefox 146.0.1 compared to Microsoft Edge

Status: UNCONFIRMED

(Core :: Networking, defect, P3)

Description

[Jeff]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0

Steps to reproduce:

1. Start Firefox from desktop (I have the app pinned to my taskbar)
2. Go to https://www.speedtest.net
3. Run performance test (click Go)
4. Note results

Actual results:

Performance on Firefox: 2.35 gbps down / 1.313 gbps up

Expected results:

Performance on Edge: 2.35 gbps down / 2.28 gbps up

Expect Firefox to show similar results, however Firefox is consistently showing about half the upload speed as download speed.

My connection is 2.0 gbps symmetric (Comcast/Xfinity finally did something right), but can boost to ~2.35 gbps.

I found an old bug https://bugzilla.mozilla.org/show_bug.cgi?id=1596576 that seems to show a similar issue. Perhaps with my faster connection the problem has recurred.

System specs:
OS: Windows 11 Pro
Version: 24H2
CPU: AMD Ryzen 9800X3D
RAM: 64 GB
Networking: 2.5 gbps Ethernet

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Performance: General' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:bas.schouten, could you have a look please?

For more information, please visit BugBot documentation.

Comment 3

[Bas Schouten (:bas.schouten)]

The Performance Impact Calculator has determined this bug's performance impact to be low. If you'd like to request re-triage, you can reset the Performance Impact flag to "?" or needinfo the triage sheriff.

Platforms: Windows
Impact on site: Causes noticeable jank
Configuration: Rare

Comment 4

[Valentin Gosu [:valentin] {{ PTO 2 - 12 April }}]

This is probably a dupe of the other upload speed bugs. But given this is obvious at REALLY high bandwidths, I think it's less critical.