This is how one of these tests work. With a broadband speed test, what’s going to happen is a so called sterile file is going to be created on the fly by the testing site. It’s called a sterile file because it’s basically a bunch of “commodity” stacks of information that are used to benchmark the actual quality of the bandwidth that you’re using. Now you have to keep in mind that if you’re running a test like this, if you’re doing so from behind a router, and then from behind a router that’s servicing more than your computer, you’re going to get a reading that’s only partly true, because there are two other sources that are going to be affecting this whole situation, and that are namely: the computers on your network, and two: the router itself. Some routers are just less efficient than others, and so you want to bear that in mind.