Problems with your Demon 2+ Broadband speed

There are many possible causes of slow broadband speeds, and this guide covers the most common ones. If you still need assistance after you’ve read this guide, please contact us on 0345 272 2666, providing as much detail as possible.

Sync speed and throughput speed

The broadband speed you receive is determined by two main factors:

  • Sync speed or ‘line speed’: this is the speed of the line between your router and the local exchange, and is the highest possible speed you can receive.
  • Throughput speed or ‘download speed’: this is the actual speed you experience when using the Internet, for example when you’re accessing websites or downloading videos. It cannot be higher than your sync speed.

There are a number of things that can affect each of these. The advice that’s relevant to you depends on how much you know about the problem you’re experiencing:

  • If you know your sync speed is permanently lower than you’d expect, or it’s fluctuating, please read Section A and Section C of this guide.
  • If you know your sync speed is fine, but your throughput speed is slow, please read Section B and Section C.
  • If you’re not sure which of the two previous options applies to you, please read Section A, then Section B, then Section C.

Section A: The sync speed between my premises and the local exchange is slow

Generally, the greater the distance between your premises and the local exchange, the lower the speed you’ll be able to receive. Someone with a line that only stretches 500m to the exchange may receive a full 20Mbps service, while someone whose line is 5km (about 3 miles) long may only receive 1-2Mbps, or perhaps less. Every line is different, so even if you have two connections to your premises, they may have different sync speeds.

To make sure you’re getting the fastest possible sync speed for your premises, try the following to reduce interference:

  • Read our setup guide, to make sure incorrect internal wiring, equipment and router cabling are not causing broadband speed and stability issues.
  • Switch off the power to your router, to your computer (remember to shut down your computer first), and to your network switch if you have one. Leave for 30 seconds, then power everything back up as normal. Wait for a few minutes, then check to see if your service has improved.
  • Check for any announcements we’ve made about your service or problems in your local area, by looking on our Home page or by calling our status line on 0800 027 0384. If there is an issue affecting your service, please wait until this is resolved, then contact us if your problem persists.

Section B: The sync speed is fine, but my throughput speed is slow

NB: Please make sure your computer is the only device connected to your router when testing and monitoring your broadband speed.

If your throughput speed is only slow during peak periods (typically 8am to 10pm):

  • Make sure your usage for the last 30 days has not exceeded the FUP (Fair Usage Policy), and if it has, reduce your usage. You can check by visiting our usage page and logging in using your hostname (the part of your Demon broadband login before the @ symbol) and your connection password.
  • Bear in mind that broadband is a contended or shared service, so your speed will probably fluctuate during peak periods, sometimes significantly. This is not usually considered to be a fault.

Please check the following, whether you experience issues during peak periods, all the time, or intermittently:

  • If you normally use a wireless connection, we strongly recommend connecting your computer to your router with a network cable, at least for testing purposes. Ideally you should disable wireless capability on your computer when you do this.
  • Make sure your virus, malware and spyware protection is up to date, as these malicious programs can abuse your connection without your knowledge.
  • Check that it’s not just one website you’re having problems with by testing others as well.
  • Bear in mind the service you’ve purchased. If you have an 8Mbps service, that is the maximum speed you will receive, even if your sync speed to the exchange is 15Mbps.
  • Check that your computer isn’t running programs such as file-sharing applications and online backup software in the background, as these can use your Internet connection continuously for long periods. Even large Microsoft Windows updates can take a long time to download. All of these applications can slow your broadband speed.
  • Think about other users’ activities. Ensure other computers or even games consoles on your network aren’t causing the problem.
  • Make sure your wireless router is secured with a password to prevent anyone within range using your connection whenever they want. If we supplied your router, it will already be secured, but if you purchased your own then consult the manual and set up a WPA key.  The easiest way to check if your wireless is secure is to try to connect something new to it (such as a different laptop or a smartphone). If you are not prompted for a password, or are able to connect and browse the Internet without specifying one, then your wireless is not secured.

Section C: Contacting us

If you’re still having problems after reading Section A and Section B, please contact us on 0345 272 2666 so we can investigate the problem. First, however, you’ll need to gather some information that we’ll ask you for when you call:

  • Whether your service has always had this problem, and if not, when it first occurred.
  • Whether there have been any recent changes that might affect your service. A new extension socket or another telephone being connected can impact your service, but think about less obvious things such as environmental factors too. Even Christmas tree lights, electricity generators and welding equipment can cause problems.
  • Run several speed tests at different times of the day, ideally using a couple of different speed test websites each time. You should test at about 6-7am (or 2-3am), around midday, and about 8-9pm to give a clear picture of how your speed varies throughout the day. Please make sure your computer is the only device connected to your router when testing your speed. Copy and paste the results into a text document or take a screenshot to email to us, or if you can’t, take a note of:
    • Which speed test site you used
    • What upload and download speeds you achieved
    • The time you performed the test

There are many different speed test websites available on the Internet, but we recommend and

Please remember that the more information you can provide, the faster we’ll able to resolve the problem.