Home / Channel / General Tech / BT Infinity does badly in real world speed test

BT Infinity does badly in real world speed test

In the UK, we accept that broadband speeds can be variable, but we also expect a connection to exist almost everywhere we go. Recently, BT has pushed a wad of money into the creation (and marketing) of its ‘Infinity' product. It's supposed to deliver the very best experience possible – but how fast is it? We set up a novel test to see how well BT Infinity really works.


You can get as scientific as you like with a broadband speed test, but there's nothing like the ‘Genuine every day user experience' to give you the real flavour of what's going on and whether a service really delivers.

With BT Infinity, we were told that 70Mb/s download and 19Mb/s upload was possible. That is ACTUALLY what was delivered. But once you start using it, what happens?

Location, Set-Up and Contention
With a KitGuru associate located very close to a modernised exchange (almost exactly ‘line of site'), we checked carefully on the initial installation process. The BT engineer confirmed that there was no one else using BT Infinity on the local box – which means that we managed to largely eliminate ‘contention' from the equation. Contention is when a service DOES provide a huge amount of bandwidth, but there are 50 other people using the same connection – which limits what each person can have. Having BT's engineer confirm that this was not going to be an issue, helps us understand more about BT's actual network – rather than random variations for locals. We tested the BT Infinity system using a laptop plugged directly into the back of the router – the ‘check' was done with using a handheld Wi-Fi device from ‘3' which we accessed using a Blackberry and the original laptop.

BT Confirmation that ‘All is well'
Before starting, we placed a call with BT to say that there were ‘Issues with the broadband connection'. Using our knowledge of networking and the interwibble, we managed to convince them to send an engineer out. He dutifully told us that any issue must have been ‘a one off', BT's network was working properly and that, after testing, BT was sure that ‘everything was working properly at their end' and ‘It checks out perfectly'. Nice.

Confirmation System
We purchased a hand held, Wi-Fi, broadband solution from ‘3' to use as a system checker. If, at any point, we discovered a drop in line speed using a hard wired connection to the BT Infinity box, we could immediately switch to wireless over the portable Wi-Fi device and see what speeds were achievable – using EXACTLY the same hardware (in terms of PC), but with BT Infinity ‘removed from the testing loop'. Over the 5 day period, we would do the testing with BT Infinity and then run Broadband Speed Checker with the hand held device as well.
The ‘3' Wi-Fi unit showed almost zero variation in performance over the 5 days – so we're certain that the equipment at our end was (a) fine and (b) didn't change.
The shot below shows a ‘typical connection scenario' with the ‘3' Wi-Fi device and a Blackberry: 5.73Mb/s download and 1.53Mb/s upload.
Satisfied with out ‘simple, but effective real world methodology' we began.

It's sad to see a poxy '3' device smash BT Infinity for speed on such a regular basis. Remember, a BT engineer confirmed that everything was fine with Infinity before we started. Graph paper background selected to make everything feel more scientific.

Kick Off

Having spoken to our operative, we believed that delivery from BT Infinity was ‘wobbly' – despite the onsite BT engineer's confirmation ‘100%' that everything was OK.
Remember, we checked with BT's first, second AND third line support teams – AND we made them send out an engineer to confirm everything was ‘working perfectly'.
We decided to take the first reading on Thursday 21st June 2012. We varied the times of day when we tested, to try and map the ‘real world experience' of living with BT Infinity.

Before you look at the pictures, would you care to hazard a guess as to just how ‘fast, reliable and stable a perfect BT Infinity connection is'?

BT Infinity: The Real World Experience

Thursday morning, pre lunch time rush hour, we have 1.59Mb/s coming down while a monster 7.17Mb/s head up the connection. Whenever you see your upload speed arse-master the download like this - you know it's wrong.
Later the same day and we have 5.43Mb/s coming down, while the upload speed is 6.35Mb/s. Still not right. Remember, '3' gives the same download speed.
Let's try Friday afternoon. This time BT Infinity offers 13.09Mb/s down and 2.92Mb/s up. It's starting to look right. Starting.
Saturday lunchtime and we're back in the toilet with BT's expensive Infinity. The '3' mobile Wi-Fi device is looking amazingly reliable as BT's poxy Infinity only manages 5.62Mb/s down with 2.99Mb/s up. This is getting sad.
By now, you're wondering if the BT Infinity connection ever delivers the kind of speeds we're promised in the advertising. Sunday evening sees 10.85Mb/s coming down with 5.88Mb/s going up. Respectable, but rare.
Monday morning, just after the masses hit the web for an 'email and Facebook catch-up', BT Infinity manages 19.32Mb/s down with 7.38Mb/s up. This is better, but still under HALF what was promised on installation.

Taking all of this data together, we can plot a graph of what is delivered against what has been offered. To say that the BT Infinity experience ‘falls a long way short of the offer' is an understatement. Before we sign off with a final graph, let's be clear again:-

  • On delivery, the BT Infinity system being tested would regularly deliver around 30Mb/s download and more than 10Mb/s upload. That's only around 50% of the offer, but it's probably ‘good enough' in the real world
  • BT engineers checked everything for us – before we tested – and confirmed that all of the equipment was working fine, that there was almost no contention on the box in the street and that the local exchange was very close and in a straight line from the installation
  • We checked during different times of the day and, on each occasion, compared the result to a handheld ‘3' Wi-Fi device. In some cases, the ‘3' device was close – in others it won. Which should never happen on a ‘BT checked, fault free system'

Recently, BT adverts for high speed broadband have been banned after the Advertising Standards Authority upheld multiple complaints that the network delivery does not match the advertising. We have to agree with the ASA. While the ASA focused on BT's inability to beat other high speed broadband services, our real world testing shows that it actually struggles to beat hand held devices as well. We've contacted BT for a comment.

BT Infinity is all over the place - and FAR below the promised speeds that WERE achieved when first installed. All of the equipment has been checked and passed by an onsite BT Infinity Engineer visit - so must we conclude that BT's network is screwed ?


One last gem from BT. Despite the fact that BBC, Telegraph, Independent, Guardian etc all say that Broadband Speed Checker is a great tool, BT thinks it has a better one. However, it is ‘Flash only and not compatible with Apple technology'. Whoops.

KitGuru says: From this test, it looks like BT has got a LONG way to go. There were times when we achieved a MUCH better result with a handheld ‘3' internet connection device than we could with BT Infinity. Which is really sad. The variation in speed was amazing. Also, you have to have the patience of a saint to go through with BT's first and second line support to try and identify an issue. We believe that there are issues with BT's high speed broadband network and these are not being addressed anywhere near aggressively enough.

Comment below or in the KitGuru forums.

Become a Patron!

Check Also

Leo and DaPoets on AMD vs Intel in 2024

While at a press event last week, Leo met up with Terrence, AKA 'DaPoets' to talk about the upcoming Ryzen 9000 processors. Naturally, the discussion soon turned to AMD vs Intel in the 2024 landscape with Arrow Lake coming up...


  1. Please tell me those results come via a wired connection and not that blackberry pictured above.

  2. @Jamie: If you check the BOLD parts in the opening section, you will see that this was a case of hardwired BT Inifinity against the weakest wireless handheld situation you could imagine. And the handheld won HALF the download tests. Which is pretty embarrassing.

  3. Did you try any other servers, or try any other method besides synthetic methods to test the speeds? I just used that site and only managed 20 down on a 50 connection while I can happily download content at 6MB/s all day from the likes of steam.

  4. Really poor testing methodology. Using only one source is the biggest no-no possible and really discredits your approach. As mentioned above, any weakness seems to lie with the speedtester used and can’t be attributed to your Infinity connection.

    In order to make your analysis legitimate, you must redo the whole thing using mutiple synthetic tests (local servers from speedtest.net), as well as real world scenarios.

    Glaringly short-sighted. Deliberate ploy?

  5. My brother-in-law has Infinity and was regularly getting 30-40Mbps. That was until BT replaced the modem (unasked for) because the one he had was from a faulty batch! Interestingly enough, he is now receiveing similar ‘fluctuations’ and speeds as the Gurus did above and BT refuse to admit there’s a problem!

    Personally, I’d probably have cancelled the contract, or at least threatened to, as they’re not providing the service that’s being paid for.

  6. im not really sure this is an analysis. just a test as it says in the title.

    I have the same package as the author and it was great for the first month I had it. now its all over the place with newsgroups, software and other testing programs. its a pants service and im moving.

  7. I tried broadbandspeedtest.co.uk and I tried my usual speedtest.net
    and with my 50Mb virgin broadbandspeedtest gave me 19Mbps and speedtest.net showed the full 50.

    Test again with different speed testing tools please.

  8. I tried with my 100mbit virgin media and got 15mbs this evening with both speedtest and this tool.

    Tried last night and got 89 mbit.

    Uk internet sucks ass. Simple explanation for it all. We need to sue all these losers.

  9. Terrible test (nothing real-world about it!) with inflammatory title – clearly some other agenda here

  10. I’m getting 64 Mb/s on 80 Mb/s package. File download-wise I often enjoy downloads reaching 10MB a second. The connection quality you get is down to your locality; exchange capacity/contention ratio(other customers)/distance from exchange/quality of the last mile(copper phone line). My distance from the exchange dropped my connection to 64Mb/s. There are not many BT Infinity customers as this is a cabled area so I enjoy very good service. So my advice is to join the real world and understand the meaning of ‘upto’ and ‘possible’.

  11. I’ve had Bt Infinity for approx 3 months now and phone them up every other week as the signal slowly drops after the phone call where they say just just do “a quick test”
    my signal shows ave 30mb/s but when actually using it its very very slow (slower than my old sky broadband which was 3mb/s… I was paying for the sky 10mb line) I even have to turn off the Wifi on my iPhone as the 1.2 mb/s local 3G is far quicker.

  12. Mr and Mrs Infinity

    BT infinity 2 – the 70/20 service has had issues with *some* FTTC Openreach equipment overheating,so our initial 70 Mb down 18 Mb up became limited after they came back with a different unit urging us to let them replace it without an appointment.
    Ping on the so called faulty unit was 11 ms – it’s 25 ms with the replacement .Speed immediately dropped and has stayed at 50- to 56 Mb down and 11-16 Mb/sec upload. But this is still a consistent speed and the service is very reliable. Someone appears to be confusing Mb and MB in this article.There is no way on this earth any handheld device on a 3g connection could match BT infinity2 speeds,even 4G is a little off the best infinity2 speeds we get

  13. Infinity Pensioner

    Something is DEFINITELY amiss with those tests.

    Using the http://www.broadbandspeedtest.co.uk I am told I am achieving 25 up / 8 down on an Infinity 80/20 package.

    Using http://www.speedtest.net I am told I am getting 75 down / 18 up.

    Having migrated/escaped from the dreadful Virgin 20mbs, I can confirm that buffering, whether from the TV players, YouTube or international TV is a thing of the past.

    This old cat found the cream!

  14. http://www.broadbandspeedtest.co.uk is a shocking source to test with. It fluctuates all over the place. I have seen this at various locations all running various ISPs. Speedtest.net whilst not perfect is far more reliable. Thinkbroadband is another much better test source.

  15. After more calls to BT, they confirmed “No fault found on the line” and it continues to go up and down like a yoyo. When you walk along the road and see the state of the BT boxes – all smashed up and open to the elements – it makes you wonder.

  16. Why is everybody so surprised that BT can’t provide decent speed to all? The cables have been rotting in the ground since 1955 and there really is no way to send a highspeed service over those cables at real word distances no matter what fake tech terminology they come out with to make it sound good. Just face it you can’t get fibre. Its still DSLovr unshielded wires from the cabinate!!

  17. Patricia Marchand

    Ah, BT infinity, bad for:
    – speed slowing right down from 6pm
    – support attitude problem, they think we are all wrong and they are right!
    I complained and just been told ‘BT does not guarantee any speed’, so if it is the case they should not advertise as infinity ‘been the fastest broadband ever’, should they?
    Any way I have enough and leaving them.

  18. We have infinity and we have between 5 and 10 devices connected and cat 6 throughout the house with 4 laptops and 1 server.every one in the family has a smart phone and so there is a lot of traffic / basic chatter. What is really difficult to accepted is sustained download speeds. So streaming media to the ps3 from the Internet always gets into difficulties, even if we are all just sitting watching TV. Putting a meter on the service we get suddenly 5 secs with a download rate of 50k, and then it shoots back up. In addition large file downloads or upload take longer than burst tests would suggest. Comparing this to my friend in Germany, who sits for the same price on a 1gbs line is like comparing chalk and cheese. How can we be so far behind?

  19. terrible service.. i’m getting 19mb if i’m lucky on infinity….the reality is, BT’s inferior network will never get close to virgins fibre speeds, they’re literally 10 years behind in terms of infrastructure, they should have started small with a 30mb connection and worked their way up.. instantly promising 100mb connections was never going to end well..

  20. @Telecaster: There are no 1GBps lines in Germany. Stop spreading propaganda just because your “friend” is fooling you.

  21. I have 38 mb fibre 30 meters from the box and get 37.5 right up until the American market opens at 13:00. It then drops to between 16 mb and 0.5 mb. (using the BT test website)
    BT claim nothing wrong… Work that out!!

  22. Something sounds amiss. I get ~35-40Mbps Down and reliably 8Mbps Up and I don’t live particularly close to my exchange. I had sky previously on a 20Mbps package and never got more than 2Mbps! Infinity has been amazing for me, games, movies, TV’s, download, never had any issues. The Home Hub has needs restarting once every few months but that’s about it. Your results sound VERY odd…

  23. Hey I think its pants also..fluctuations are common every day occurrence. .phone bt fer 6 days now cause the wireless is always cutting out…every time I ring they won’t let me speak to a manager and just reset the router. .refresh the equipment in deeslam and it works for about 30 mins pile a dung

  24. It seems I’m the only one getting the advertised speeds. No matter what time of day I am getting excellent speeds. I’ve had infinity now for two weeks after dumping Sky due to their awful service after a forced switch over from BE. I couldn’t be more pleased.

  25. I completely agree with you, The Governments incompetence and reliance on Privatisation has led to BT becoming to almost Sole (economically feasible for common consumers) provider of Infrastructure in the UK.

    My Area has been “Under Review” by OpenReach for more than 2.5 Years, when asked to comment on an ETA or at least assure us that BT Infinity will be enabled in our area, AS PROMISED To the Government in return for Subsidies and the rights to lay lines, there is no answer.

    Funny that.

  26. I have BT infinity and the speed goes up and down like a yo-yo. BT are promising speeds that do not happen. Very frustrating.