There are four main properties that determine the quality of a DSL Internet connection: download speed, upload speed, "ping" and "packet loss." Download and upload speed are the ones most people pay attention to, but ping and packet loss are more important in applications requiring quick responses, like online games. Download and upload speed is a measurement of how much data per second your DSL connection can receive from and transmit to the Internet. "Ping" measures how long it takes for a signal to go from your computer, to another computer and back to your computer. "Packet loss" measures what percentage of data is lost in transmission between your computer and the Internet. High download and upload speeds with low ping and packet loss are the mark of a high-quality DSL connection.
Cancel any active downloads and close programs that access the Internet. Don't forget about software updates and file-sharing programs.
Go to an Internet speed test site. There are several to choose from online, such as Speakeasy and Speedtest.net.
Select the location closest to you if given a choice. If the website does not give you a choice, proceed to the next step.
Start the test. The exact phrasing of the button to start the test varies; it's usually some variant of "Begin Test" or "Click here to start test." The computer displays the results after downloading and uploading a certain amount of data.
Visit one or more of the other speed test services and run tests there. Different tests perform differently; running more than one is the best way to get an overall picture of the speed of your DSL line.
Go to a ping and packet loss test site to determine your packet loss rating. Lower ratings are better.
Run these tests in the morning or early afternoon while most people are at work. The more people using the Internet in your area, the slower your connection will be.