Broadband speedtest

What can affect your broadband speed?

Broadband speed is affected by a number of variables, including:

• What plan you're on: Your ISP can limit the speed available to you.
• How many users are sharing the copper wire to a phone exchange and how far you are from an exchange: ADSL broadband slows down when more people are sharing a cable. The cable leading from your home to the telephone exchange can only transfer so much data at a certain speed. The more people using that cable and the more data they're trying to move, the slower it becomes. Think of it like a motorway - at 5am when the roads are empty, you can drive along at a good pace, but at 5pm when everyone wants to use the road - gridlock. The same happens with ADSL broadband.
• The amount of traffic at a website and the amount of traffic with that ISP: The same slowing-down process happens at websites. If everyone tries to access one website at the same time, the cable can't handle the demand and sometimes the website will not be accessible ('crash'). If you're surfing the web, some websites of the same size will load faster than others because they're not so busy.
• Your computer setup: If you have an old computer and/or it's setup inefficiently this can slow things down e.g you only have a tiny amount of free memory and your computer is forced to use your hard disk to store temporary data which slows things down significantly.

Why are broadband speeds always shown as maximum speeds?

Because the speed of ADSL and cable broadband is affected by the variables outlined above, ISPs can't guarantee a certain speed. So they are allowed to quote the broadband speed as the maximum possible speed.

How does this test work?

The test performs a very small upload and download tests prior to the real tests to estimate the speed of your connection. That way we do not attempt to upload and download very large files to slow connections. Based on these results we then use one of several test sizes to accurately measure the bandwidth, by sending and receiving files of varying sizes.
Note: Depending on how busy the internet is at the time, there can be a fair degree of variance of the results that you get from this speed test even when you run several tests back to back. You may wish to run the speed test a few times and average out the results to get a more accurate reading.

Source: http://www.consumer.org.nz/reports/internet-providers/broadband-speedtest