Internet Speed Test Much Lower In Firefox Than Ie - Why?

OS: Windows 7 Home Premium 64 bit
Hardware: ASUS laptop K52F
Internet connection: DSL hard wired
Using Frontier "Broadband Max" with nominal download of 3Mbps
Firefox version 45.0
IE version 11.0.9600.18230
Location: Morgantown, WV

When I use the Frontier speed test (https://speedtest.frontier.com/) on Firefox and IE, I get the following typical results (averaged over 5 tests for each browser) from a Frontier Chicago server:
Download : Firefox 1.7-2.0 Mbps, IE 2.6-3.1 Mbps
Upload: Firefox 0.7 Mbps , IE 0.7 Mbps
Latency: 41ms for both

Firefox:
-- All extensions have been disabled
-- The only plug-ins enabled are Shockwave Flash, Silverlight, Primetime Content Decryption Module by Adobe, OpenH264 Video Codec by Cisco
-- Configured to not remember history

Why should there be such a big difference between browser? Am I doing something wrong? Is there a configuration change that would make a difference for Firefox?
I tried "refreshing" Firefox - no change.

 

The only way to get true comparative speed tests when doing them via a web browser is to clear all cache and cookies first, do a test with one browser, then shut that browser and clear all cache and cookies again, then do a test on the second browser.
I don't know who Frontier are, but I would use http://www.speedtest.net/ as it has a good reputation.
Aside from all that the speed tests are not that relevant to actual real-time browser usage - they are just an artificial snapshot at one moment in time.

 

I DO clear cache & cookies prior to the test and only have one browser open. Frontier Communications is a nationwide telecom and ISP. Frontier will only accept speed test results from their own online speed test app.
Yes, it is a snapshot in time. But I think it is still relevant if the results are consistent.

 

OK that's fine.
A person can test their speed on any browser-based online speed test site they choose irrespective of their ISP, unless your ISP want to know speeds based on their own site tests if you are actually communicating with them about poor speeds.
So it comes down to the experience of using those web browsers, and whether the surfing experience is noticeably and significantly slower with one browser compared to the other. If that's the case then you just have to decide which one to use.
Online searches show very similar variations in speeds among Frontier users.

 

my own personal experience with speed tests... i stopped using them, because in my situation, they are not accurate. deep in our suburbia neighborhood, the at&t box is about a quarter mile from my house. trying about a dozen different speed tests, from various sources, showed our broadband speeds to be roughly what at&t said we should get. however, we were lucky to get a tenth of that speed, maybe 700KB download, not the 6MB we signed up for. the internet was still usable, but you want to be able to get what you pay for, so we spent about a month with 5 different techs from at&t to troubleshoot the speed deficient. the upshot, all of the at&t techs were surprised that the internet even worked for us. the type of copper wire connecting our house to their neighborhood box, and the length of the connecting wire, roughly 1300 feet total, made it physically impossible for us to get the broadband speeds that we signed up for, and the techs all said that if they did the initial installation, they would have aborted the install because we would never be able to get the advertised speeds, even in their slowest offerings. yet, i can do any online speed test and be told that our download and upload speeds are roughly what at&t said we should be getting. that was about 3 years. oh well, it is what it is, and that's why i don't bother with speed tests any more.