Computerworld tested the 3G networks of AT&T, Sprint and Verizon, with a cellular data network connector on a Lenovo ThinkPad X300 and found AT&T's network to be significantly faster.

"In tests, AT&T's network left its competitors in the digital dust, with average download speeds of 755 Kbits/sec. and average upload speeds of 484 Kbits/sec. The peak download speed was 1.6 Mbits/sec. It connected in just 3.0 seconds and loaded the test Web page in 0.228 seconds. On the downside, the cellular modem ate up 40 minutes of battery time, midway between Sprint's hour and Verizon's 20 minutes," Brian Nadel wrote.

In the conclusions, the author pointed out some good things to know. Since it is cellular technology, the current throughput at any given time can rise then fall dramatically. Also, the current networks are still a work in progress.

"You should also be aware that, even though the service providers say they use the latest technology, their coverage is a mix of old and new. For example, on several occasions while testing on Sprint and Verizon, rather than connecting via the current-generation EV-DO 3G technology, I could see in the user interface that I was connected via 1xRTT, an older and slower technology. All three networks are currently building out their newest-generation networks, so it's a work in progress.

Finally, 3G coverage is good in the largest cities, but out in the plains of the U.S., the three providers have not implemented coverage. Customers need to check the carrier's Web site for 3G coverage maps.

Apple iPhone customers will be pleased to know about these results from Computerworld, especially when Apple finally ships its long awaited iPhone 3G. That is, if they live in a large metropolitan area in the U.S.