FTTP speeds measurement - via browser or specific app?

I am in a new build home which came with an Openreach FTTP connection complete with an ONT installed. I chose the full 900 package with Zen but have been disappointed at the speeds I have been getting. Zen's technical support have been getting me to carry out various diagnostic tests including connecting direct from my desktop PC by ethernet cable to the ONT so bypassing my wiring and the Zen Fritz router.
Yesterday, initiated by Zen, two guys from Openreach came. They changed the ONT, re-spliced the connection outside the house and made various other checks including the fibre network routing. This has improved speeds considerably. I have now found this morning that running a speed test through a browser (Edge or Chrome) with just the one tab open and no other apps running gives much slower speeds than if I use the dedicated Speedtest.net app which I have only just discovered. This has left me confused as Zen itself has a browser based link on its website to a customised version of Speedtest.net. What should I believe? How can I really check if I am getting the speeds that I am paying for?

In reply to a post by chriswillsher:

I am in a new build home which came with an Openreach FTTP connection complete with an ONT installed. I chose the full 900 package with Zen but have been disappointed at the speeds I have been getting. Zen's technical support have been getting me to carry out various diagnostic tests including connecting direct from my desktop PC by ethernet cable to the ONT so bypassing my wiring and the Zen Fritz router.
Yesterday, initiated by Zen, two guys from Openreach came. They changed the ONT, re-spliced the connection outside the house and made various other checks including the fibre network routing. This has improved speeds considerably. I have now found this morning that running a speed test through a browser (Edge or Chrome) with just the one tab open and no other apps running gives much slower speeds than if I use the dedicated Speedtest.net app which I have only just discovered. This has left me confused as Zen itself has a browser based link on its website to a customised version of Speedtest.net. What should I believe? How can I really check if I am getting the speeds that I am paying for?

Download a large file of a known size (for example from the TBB main site) and time how long it takes.

You haven't actually told us the speed you are receiving via the speed tests.

Also various speed tests will give differing results, depending on the time of day and backhaul etc. also remember that many smaller sites (in general) have connectivity of only 1gbit.

Ftp, which is used to transfer files, is probably the most efficient way to download large files and even then speeds may fluctuate. The max you will see on a public ftp server is an 8gb linux iso file which won't stress a gigabit connection.

I took made several test within a few minutes. The official Zen test at http://speedtest.zen.co.uk/ gave a best result of 375Mbps, using speedtest.net got 408Mbps. Switching straight to the Speedtest app I attained an average of 714Mbps and a peak of 913 over 8 tests in quick succession.
It has been suggested to me that a browser test will just d/l a single thread whereas the desktop app might try multiple threads to saturate the bandwidth.
Given that ISPs such as Zen guarantee a minimum d/l speed it surprises me that there isn't a definitive test across the industry by which this is measured.
I have concentrated on the download speeds as the upload has been consistent across all the tests close to 100.
I appreciate that having never had a really good internet connection before, I am on a steep learning curve,.

Speedtest.net does not provide the speed test for Zen.
The speedtest for Zen is provided by Think Broadband.
May be worth testing the Think Broadband test directly as that does single and multi thread, also the speedtest.net website gives the option for single or multi thread

Thanks
Dan

Hi,

Have you tried using the CLl version of the speedtest from Speedtest.net? I use that even on my Ubuntu box as it uses less overhead than even the app. One question that you do not answer is (IMHO @ least...): what OS are you using? Windows 10/11? A flavour of Linux? Android?? Once you answer that question you might get some better answers.

HTH,

Thanks for your advice. I am running Windows 11 Pro 22H2 (fully patched and up to date). Sadly, as far as I can see the CLI version of Speedtest is not available for the Windows environment.

@ChrisWillsher,

I have the CLI on my Windows 10 tablet & laptop (all fully up-to-date). So there is a CLI for WIndows (here is the link for the x64 Windows Command Line Interface). It definitely works as I use it nearly every day...

HTH,

In reply to a post by chriswillsher:

I took made several test within a few minutes. The official Zen test at http://speedtest.zen.co.uk/ gave a best result of 375Mbps, using speedtest.net got 408Mbps. Switching straight to the Speedtest app I attained an average of 714Mbps and a peak of 913 over 8 tests in quick succession.

is this done on the same device or different?

In reply to a post by chriswillsher:

It has been suggested to me that a browser test will just d/l a single thread whereas the desktop app might try multiple threads to saturate the bandwidth.

That is simply untrue. A modern browser on a mac or pc can use many threads and multiple network connections

Many thanks. That's brilliant. What a difference. Speedtest.net multi ~390, Speedtest app 534 and Speedtest/Ookla CLI 840Mbps. I'll never believe a web based test again! All three tests run within the same 3 minute period with nothing else running.