Broadband Troubleshooting: Slow Speeds

Is your broadband running slow, or not as fast as you'd expect? There may be a line fault, a problem with your equipment or your line might not be able to go any faster than it is now. This guide will show you how to find out and what you can do about it.

How fast can your line go?

Before you start troubleshooting, you need to know how fast your line can actually go.

Put your number in the BT Availability checker. The results will confirm the exchange you're on and the maximum speed your line can support.

What's causing the problem?

Run a BT Speedtest (see our BT Speedtest guide if you need help). The results will show your current speed and how your line is profiled.

In order of importance, the stats you should look for are:

1. DSL Connection Rate (DOWNSTREAM) - this is the speed of the connection between your property and the exchange, it should be close to the figure reported by the BT Availability Checker
2. IP Profile - this is the fastest speed you can currently get whilst also receiving a stable connection. This should be just under your DSL Connection rate
3. Download Speed - the actual speed you're downloading at, this should be close to but never higher than the current IP Profile

If you're having speed problems, one of these figures will be lower than you'd expect. Click the appropriate link below and we'll show you to troubleshoot and report the problem:

• The Downstream Rate is lower than it should be
• The IP Profile is lower than the downstream rate
• The Download Speed is lower than the IP Profile

The Downstream Rate is lower than it should be

On a stable line the Downstream Rate should be close to the maximum speed reported by the BT Availability Checker. In the event of a problem, the Downstream Rate will reduce to try and keep the broadband service stable.

Before reporting a fault, you should check everything mentioned below to make sure your equipment is set-up and working properly.

Please Note: A low downstream rate will also reduce the IP Profile. If your downstream rate increases at any point, it needs to stay that way for 2-3 days before the IP Profile increases. See our High-Speed Broadband Guide for more information on this.

Why do I need to do this?

If we raise a fault to our supplier and an engineer finds that it's caused by something within your control (like your equipment or settings), you'll be charged for the callout. We'd rather that didn't happen and we're sure you feel the same way.

Make sure your telephone line is working

You'll see problems with your broadband if the telephone line isn't working properly. Pick up a telephone handset and check for a dial tone:

• If the line sounds clear and you can hear a dial tone, go to Check your microfilters
• If the line is noisy or you can't hear a dial tone you should report the problem to your telephone provider - if that's us go to the Telephone Troubleshooting Guide

Check your Microfilters

Broadband shares the line with your telephone service. Microfilters separate the signals and prevent one from interfering with the other. Subsequently, anything connected to your line needs to pass through a microfilter. If you need help with this, our Fitting Microfilters Guide will show you how to set them up properly.

If your microfilters are fitted correctly and your downstream rate is still low, go to Test from the master socket.

Test from the master socket

Make sure your extensions and cabling are ok by testing your broadband in the master socket.

You'll find it at the point where the telephone line enters your property. Most look like this:

To test, unplug everything from your line (including TV equipment and all microfilters) and connect your router to the master socket through one microfilter.

• If the downstream rate increases: Either your extension wiring or something connected to your line is causing the problem. Find out which by checking after plugging each piece of equipment back in. Try replacing your microfilter(s) if you can't find the culprit
• If the downstream rate remains low: Go to the next section - Try a different router/modem

Try a different router/modem

If possible, try a different router or modem on your line.

• If the downstream rate increases: Your hardware is faulty and needs replacing, if you got it from us in the last 12 months then contact us for a replacement
• If the downstream rate remains low: This rules out your hardware as the cause of the problem, go to the next section - Report a fault

Other things to consider

Has anything changed recently - either with your setup, in your property or the local area?

Bad weather, Christmas lights and new telephone handsets have been known to cause problems in the past.

Report a fault

If you've tried the suggestions on this page and your downstream rate is still lower than you'd expect, report the fault by calling us or via the Broadband Fault Checker

The IP Profile is lower than the downstream rate

The IP Profile dictates the maximum speed you can download at, it's set at your telephone exchange and will vary according to the condition of your line. In the event of a problem, the downstream rate will be reduced to try and improve stability. When this happens the IP Profile will quickly reduce to match. It will only rise if a line remains connected at a higher downstream rate for 2-3 days.

Bearing the above in mind, if your IP profile is considerably lower than your downstream rate, the problem will fix itself within a few days if your connection is stable.

If the problem doesn't fix itself within 2-3 days, your connection is probably dropping out - go to troubleshooting for a dropping connection.

The download speed is lower than the IP Profile

In ideal conditions the download speed will be just under the IP Profile. If there's a considerable difference, check the things mentioned below before reporting a fault.

Why do I need to do this?

If we raise a fault to our supplier and an engineer finds that it's caused by something within your control (like your equipment or settings), you'll be charged for the callout. We'd rather that didn't happen and we're sure you feel the same way.

Check Service Status

If there are problems on our side of the network, we'll post about them on Service Status. If a speed affecting problem is open, make sure it's closed before checking anything else.

Check for Viruses and Spyware

Viruses and Spyware can slow down your computer and subsequently your download speeds.

There are a number of free programs (such as AVG and Spybot) which can help you find and remove these from your system. Run a full virus scan to make sure your computer is ok.

Check your internal network and hardware

If you're using a wireless network, try connecting with an Ethernet cable. If this shows improvement in download speeds you should consider changing the position of your router/computers and the channel that your wireless network broadcasts on.

If possible, try a different router or modem on your line. If this fixes the problem, your hardware is faulty and needs replacing (if you got it from us in the last 12 months then contact us for a replacement).

Exchange Status

Problems at your telephone exchange can affect your broadband speeds.

Put your number in the Usertools Exchange Checker to find the current status of your exchange. If the VP (Virtual Paths) status is 'Red' then you might see slower speeds, particularly at peak times. If this is the case, BT will already be aware of the problem and they'll be planning to expand the exchange capacity to fix the problem.

Traffic Management

We prioritise all traffic on our network, based on traffic type, account type and the time of day. Read our Traffic Management guide to find out how and why this is implemented.

Traffic Management shouldn't cause any serious problems. If you're noticing lower speeds on a particular application, our Broadband Download Speeds page will give you an idea of what you can expect at different times of the day.

Report a fault

If you've tried the suggestions on this page and your download speed is still lower than you'd expect, please report the fault by calling us or via the Broadband Fault Checker

This page last updated 22nd February 2010