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What's causing significantly lower download speeds tested in Firefox?

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  • Last reply by NoSpam

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Running a speed test in Firefox will show lower download speeds, in some cases just a fraction of the speed of my broadband connection, both on Windows and Linux installations of Firefox Browser. Safe Mode makes no difference. Other browsers show normal speeds.

Running a speed test in Firefox will show lower download speeds, in some cases just a fraction of the speed of my broadband connection, both on Windows and Linux installations of Firefox Browser. Safe Mode makes no difference. Other browsers show normal speeds.

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Can confirm this is an issue with ViaSat network. I ran Ookla Speedtests using two different endpoints (Enid OK & Sprint, KC & Wilson Comms) on Firefox, M$Edge, Chrome, and ViaSat's own browser. The last three browsers ranged intermittently between 30.9 and 54.41 Mbps, while Firefox consistently limped along at 3.61 to 4.09 Mbps. Tried in Firefox safe mode as well, with no differences whatsoever. This is easily replicated, here. Firefox download with Ookla consistently tests at 10% the rate of other browsers.

I also attempted the same tests on the same browsers using AT&T instead of ViaSat. Firefox has consistently lower download speeds. I intend to find a speed test other than Ookla Speedtest, as this could be *their* issue with Firefox.

Being a long-time Mozilla/Firefox user & advocate, this performance failure is what it finally took to make me try M$Edge.

Edit: A test using Speakeasy with ViaSat and AT&T on all four browsers indicated that this is likely an issue with Ookla Speedtest. Speakeasy's indicated download rate for Firefox was still noticeably slower than the other 3 browsers but it wasn't any where as slow as Ookla indicates. And, you could see that the download rate was still increasing at the end of the test period, so it's not too much to assume that given a longer test interval, Firefox would have posted similar rates.

Conclusion? If you're seeing slow network speeds using Firefox and Speedtest, grab a different test website and browser. I'd say that Mozilla ought to contact Ookla and ask them what their issue is. It isn't a user issue.

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