Download speeds on BT FTTP slow when not using a VPN

I just upgraded to the 900/110 package from BT as it was on offer for £1 extra over the 500 package
I notice in real world downloads I get nowhere near that, approx 300Mbps from Microsoft/Steam/Ea etc..

fast.com and the BT wholesale speed test always come back at 900+, so as far as BT are concerned all is good. The TBB speedtest varies a bit.

However if I enable a VPN on my PC and use that, all downloads are at near full speed, the tbbx1 test is vastly different.

Is this an issue within the BT network or just my local exchange.


Without VPN



With VPN

Edited by onthenet (Thu 22-Dec-22 11:41:38)

For most users, getting poor speedtest results on high-bandwidth links is the result of problems at the client side. For example, your Windows anti-virus may be scanning stuff down the normal link, but not when the traffic comes down VPN.

I recommend you boot your machine from an Ubuntu Live CD USB stick, and do some speedtests using that. That will remove all Windows-related stuff from the equation, and give you a clean result.

If this demonstrates that everything works at full speed, then you will have been able to rule out any problem with BT's network, and know where to focus your attention on (i.e. your Windows configuration).

However if the Ubuntu test does show the same, then this rules out problems with Windows and you can more closely start investigating the upstream provider and their peering.

It does however seem very unlikely to me that BT would have a general congestion problem with traffic to TTB, Microsoft, Steam etc, and yet still be able to reach your VPN tunnel endpoint at full speed.

Thanks for the advice, I did as you said and the result without VPN is below, much better looking.



I notice the tbbx1 test is still slower.

I tried downloading the Windows 11 ISO from Microsoft and it is hitting 100MBps+

Just running Windows Defender on Win 11, which is a relatively new install, time to go to Ubuntu !!

If the only place you're noticing lower throughput numbers than you are paying for is the TBB speed test then I would just ignore the speed test.

In reply to a post by onthenet:

I tried downloading the Windows 11 ISO from Microsoft and it is hitting 100MBps+

Cool. That will be single threaded (assuming you're just doing an HTTP or FTP download, not Bittorrent or similar), so shows your link is good.

Microsoft might have a CDN node within your ISP's network, or close to it.

The Internet is a collection of independently-run networks, interconnected in a bunch of different ways. If you're only getting 400Mbps single-threaded download from TBB that could be due to a whole host of issues which are outside of the control of your ISP, and is not something to worry about by itself.

No, as stated above, it was on Microsoft. Steam, EA etc, I was only using the TBB Speedtest to highlight the issue.
However all those issues have gone with the Ubuntu install.

Awesome. Of course, if Ubuntu meets your needs then great (I'm a Mac and Ubuntu person myself).

Equally, now you know where the problem lies, it should be possible to tune Windows to work better. You'll need someone who knows the ins and outs of Windows to help you with that though.

In reply to a post by candlerb:

You'll need someone who knows the ins and outs of Windows to help you with that though.

First step is to never install 3rd party 'security' software.

Yea, I learnt that many years ago, had been just running with Windows Defender.

I have now dual booted my machine with Ubuntu and it is so much more responsive, what is going on with Windows, can it not cope with a fast internet connection.
I tried my Wife's machine ,also Windows 11 and it is showing the same symptoms as mine.

I have to laugh though, six months ago the fastest I could get was 1.5Mbps, I was using Three 4G instead, which wasn't bad.
I then had to dig a 300M underground duct to my house from the road, all ducting supplied free by Openreach and now the TBB Speedtest says I am faster than 99.8% of tests in the UK

In reply to a post by onthenet:

Yea, I learnt that many years ago, had been just running with Windows Defender.

Nice!

I have now dual booted my machine with Ubuntu and it is so much more responsive, what is going on with Windows, can it not cope with a fast internet connection. I tried my Wife's machine ,also Windows 11 and it is showing the same symptoms as mine.

Very odd.. Ubuntu is good (I’m more a RHEL / CentOS on the server type guy) but it shouldn’t be that dramatic. I’m guessing faulty Network Interface Card driver somewhere. I lead teams that support a lot of hardware and Windows (10/11 etc on desktop) isn’t incapable of 940Mbps saturating a normal GigE port.

I have to laugh though, six months ago the fastest I could get was 1.5Mbps, I was using Three 4G instead, which wasn't bad.
I then had to dig a 300M underground duct to my house from the road, all ducting supplied free by Openreach and now the TBB Speedtest says I am faster than 99.8% of tests in the UK

Awesome result!