Speed tests fast but downloads slow

Hi everyone

I have been struggling with the speed of my BT Infinity service for the last few weeks but just can't figure out what the problem is. I have 80Mb FTTH connected to a BT Business Hub 3. When I connect my laptop via Ethernet cable to the router and perform a speed test, such as the ThinkBroadband or the BT one, I consistently get around 90Mb/s reported download speeds. Similarly I get 40-80Mb reported downloads on wireless which is about what I expect.

However, general internet browsing speed has been poor for the last few weeks, but is particularly noticeable when downloading files. I just performed some tests using the ThinkBroadband test download files, found that even on a wired connection, a 100Mb download was taking over 100 seconds! In between these tests I ran the regular TBB speed test, but as usual was getting reported speeds over 90Mb/s.

I have tried turning the devices on my network off in various combinations but cannot identify any issues at my end. I initially thought it could be a DNS issue so I recently switched to OpenDNS which has improved things slightly. I have even tried a different router and switched wifi channels but nothing has made much of a difference. What is do not understand is why a speed test can give such wildly different results to a file download.

Can anyone offer any suggestions as to the cause of my problem? BT have, of course, said everything is OK as far as they are concerned. Any advice greatly appreciated. I am based in York.

Regards, Alain

Post up your speedtest ran on this site. It can report fast speeds sometimes but seeing the test and the graphs helps us see if there's congestion. Especially the speedtest that runs 6 threads at once, that often hides congestion and provides a good comparison.

Is this an XP machine - the RWIN values may need adjusting for the high speeds.

The difference between the tbbx1 and HTTP6 test is critical.

In reply to a post by pcoventry76:

DNS?

Highly unlikely. DNS is only queried once at the start of a transfer in the same way that you only look a telephone number up once before you dial. Even the worst DNS server on the planet is going to respond within a tenth of a second, to say nothing of the OS keeping its own cache.

This is also why spending time finding the fastest possible DNS server is generally a waste of time. Reliability and correctness is all that matters. Whether your responses come back in thousands of a second, hundreds or even tenths is unlikely to make much noticeable difference to the end user.

Edited by Andrue (Tue 09-Sep-14 11:20:26)

Thanks for replies so far. I can't see how to upload an image to the forum, so I will just describe the result.
Avg TBBx1 86.55 Mbps
Burst TBBx1 89.33 Mbps
Avg HTTPx6 93.67 Mbps
Burst HTTPx6 101.09 Mbps
Latency 28ms
TBB and HTTP graph lines are close to each other throughout.

Immediately preceding the speed test, I downloaded a 100Mb file from TBB, which took 2 minutes 35 seconds! I also tried a 256Mb file from cloudtestfiles.net and got similar download speeds less than 1Mb/s.

The above tests were performed with a wired Ethernet connection to BT Business Hub 3 with wireless disabled and all other connections removed.

In answer to other responses, laptop is Windows 7 but I also have a couple of Android and iOS devices that suffer the same problem. I did also try the Google DNS servers but that made no difference either.

Have you tried different browsers?

Have you tried using wired ethernet?

Have you tried this: ?

In order to rule out the Homehub as potentially being the device responsible for your speed loss, you can connect the Openreach modem directly to the PC and see if the speed improves.

To do that follow these steps:

Step 1: Remove the homehub from the modem cable

Step2: Connect your pc/laptop to the modem via the cable instead

Step3: Open network and sharing centre on windows and click set up a new connection or network

Step4: Connect to the internet then click make a new connection Broadband PPPoE

Step5: Username [email protected] and the password as BT

Step6: connect, If it doesn't,keep pressing try again until it does.


However, please note that this will stop any other access apart from the PC

That looks ok to me, but I think the images will really help.

Run the speedtest and then afterwards click copy to clipboard on the speedtest.

Then paste that here.

That's probably the easiest way to do it for you.

Thanks for that suggestion, I wasn't aware that the router could be bypassed all together. It made no difference unfortunately, still getting file download around 50Kbps. Have tried different computers , devices and browsers - they are all affected.
Regards, Alain

http://www.thinkbroadband.com/speedtest/results.html...

Obvious one, but have you tried resetting the modem?

In reply to a post by AJS23:

http://www.thinkbroadband.com/speedtest/results.html...

Your speedtest is one of the most perfect ones I've ever seen showing literally no congestion or issues. If there was congestion you would see the AVG TBB one quite a bit slower than the AVG HTTP x6 one.

This is because on a congested connection, downloading 1 file will be slow. The x6 one, downloads 6 files at once which will sort of hide the congestion a lot better.

It's like me giving you a 10Mbps connection, and you share this between 2 people.
If person 1 starts a download, they get the full speed.
Person 2 starts a download as well, now both person 1 and person 2 get 5Mbps each.

HOWEVER if person 1 starts a download, they get the full speed.
Now if person 2 starts 6 downloads at the same time, they will get 6/7ths of the speed. Person 1 will get 1/7th of the speed.
So as you can see 6 downloads at once would 'mask' the congestion a lot better for person 2.
Now amplify this case to an exchange level, it works similar.

This is often why speedtests give better speeds e.g. speedtest.net downloads multiple streams at once. So you end up being person 2 in the 6/7th example.
& is why a speedtest is often a lot lot faster than an individual download, as an individual download will use 1 stream at once, most speedtests will use multiple.

What is strange is that your speedtest is not showing evidence of this at all. I would generally conclude it's just the sites you are downloading from, but thinkbroadband is usually pretty good.

Is it ALWAYS slow? Just some sites in particular?

I was about to dismiss your obvious suggestion Andy, when I realised with a sinking feeling that I had rebooted all the equipment several times, everything that is except the modem!

And because I had overlooked the patently obvious, that was of course the cause of the problem! Having rebooted it, everything has returned to normal speeds.

So thank you for reminding me of the obvious. DOH!!

Regards, Alain

It's the simple things that we tend to overlook. Glad you're back up and running