Cambridge English has developed a site to test the speed of your Internet connection that can be accessed here:
After you've run a test the results will look something like this:
This new bandwidth checker is a better option for people wanting to make sure they have a good connection ready for test day because it tests your connection with the Cambridge based servers rather than just a nearby computer. As you can see it also tests, among other things, latency which is another important factor in determining the speed of connection.
If you have any questions about the above please get in touch and we'll be happy to help.