One of the first things that users do when they get a broadband Internet connection is to visit "speed test websites" on the Internet to measure the upload and download speed of a connection. This is great for bragging rights but also a good way to check if the advertised speed matches the real speed or if you are getting less than what you are paying for. Most Internet providers tend to use phrases like "up to" to advertise their Internet connections and depending on your location, you may not be able to come close to those speeds.
One major problem is the reliability of those speed tests on the Internet. Some show lower speeds even if the Internet connection is able to handle faster speeds. This can be due to server capacities at the speed test host, the location of the test server in the world or general routing problems that affect the measured speed.
Speed.io is the first broadband speed test on the Internet that measures the speed of an Internet connection correctly. Every other speed test is usually missing a few thousand Kbits at the very least. The service measures the download and upload speed, the maximum number of connections and the response time of the Internet connection.
The download speed test result was 14806 Kbit and the result of the upload speed test was 990 Kbit which comes close to the maximum capacities of the 16 Mbit / 1 Mbit advertised speed of the Internet provider.
The developers of Speed.io claim to utilize 50.000 servers world wide for their speed tests which seems an awful lot but would be an incredible infrastructure if this was the case. Still, it does not really matter if they have 1 or 50K servers as long as the speed tests are accurate.
Update: You may run into limits though when you run a speed test on a very fast connection. It measured my line's download speed at 45000 Kbit/s and the upload at 2000 Kbit/s. While the download speed is close to the 50 Mbit I get, the upload speed fell a bit short at 2 Mbit instead of the 10 Mbit that I have available at my disposal.