Speed testing from various OS’s

A topic that often comes up while testing a new Internet connection is how to perform a speed or bandwidth test.

Skyway West maintains a speed test server that is accessible to the general public via the web.  The server provides a Java-based test client that runs in your web browser.  The URL to access Skyway’s server is http://www.skywaywest.com/support/speed-and-voip-test.htm.  We also suggest trying other servers on the public Internet such as Speedtest.net.

It’s also important to test the network in isolation, at least when possible.  Other usage on the network at the time of the test can lower the results, but network administrators generally want to minimize downtime for their users, and taking the network out of production for a period of testing can be seen as disruptive.

It’s also worthwhile to perform the same test multiple times and compare the results.  If you get one test run that looks particularly worse or better than the rest of the runs, you should discard those unusual results and favor the typical results.

What might surprise some people is that the results of the test can be influenced by the properties of the client computer used to test with.  For example, Skyway’s full-featured test requires a functioning Java runtime environment on the client PC, but many office PC’s and tech laptops don’t have Java installed.  Speedtest.net requires a recent Flash player plugin.  Or if the testing PC is very old, slow or lacking in memory, you may find that the effort that goes into maintaining the pretty Flash or Java display of the results is actually contending with the test for PC resources.  You shouldn’t need the latest and greatest to do a simple speed test, but because of the way the test clients are written these days, that old Pentium MMX laptop may be dragging your results down.

An even more common and less obvious problem is the choice of OS.  In particular, Windows 2000, 2003 server and Windows XP have an older network stack and feature certain tuning defaults that can limit TCP performance on a wide/fast network.  Many articles have been written about how to tune Windows XP network performance, such as this one.  There are tools available for download that automate these config changes.

But before you go to too much trouble tuning up Windows XP, consider testing with a Linux, Mac or Windows 7 client instead.  With the release of Vista and now Windows 7, Microsoft has re-adjusted the default tuning parameters in their network software, and the issues with Windows 2000 and XP that would sometimes throw off speed test results are not present in Windows 7.

That’s why I recommend any tech who frequently performs network speed tests using a Microsoft OS to be sure they’re running Windows 7 instead of Windows XP.