Use SpeedTest to help diagnose Internet problems

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For the past week or so, I've been trying to pinpoint a problem with my Internet connection.

Usually I blame Comcast, my ISP, but a typical Comcast outage is exactly that: a total interruption of service. I can tell from looking at the System Tray network icon that there's no connection.

This time, however, the problem was intermittent. Sometimes my connection would slow to a crawl, other times it would disappear altogether for a few minutes. But the network icon didn't indicate a loss of service.

Time for some detective work. Sherlock Holmes has a magnifying glass; I use SpeedTest. This free service runs a quick, well, speed test on your Internet connection. It's a handy way to pinpoint the source of an Internet slowdown.

First I ran it on my laptop, a new Samsung I've been road-testing the past couple weeks. Sure enough, my normally speedy Comcast connection proved very sluggish: Download performance ranged from around 2-8Mbps, and varied wildly each time I re-ran the test. Normally I see an impressive 30Mbps (or even higher).

That alone didn't help determine if the problem lay with Comcast, my router, my laptop, or something else, but this did: I then ran SpeedTest on my iPhone (which, at home, stays connected to the same Wi-Fi network, natch). The service offers free mobile apps for Android and iOS.

Lo and behold, the iPhone blazed through the test, posting the high numbers I expected. So the problem wasn't with Comcast or my router. The problem was with my laptop. Now I could focus on other possible culprits.

SpeedTest is great for this kind of process-of-elimination troubleshooting. As long as you have another device in the house, be it a smartphone, tablet, or second PC, you can compare results side by side.

By the way, my issue turned out to be a combination of Wi-Fi drivers and a Samsung-specific Google Chrome bug—but that's a hassle story for another day.

Contributing Editor Rick Broida writes about business and consumer technology. Ask for help with your PC hassles at, or try the treasure trove of helpful folks in the PCWorld ForumsSign up to have the Hassle-Free PC newsletter e-mailed to you each week.

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