If PCWorld’s second 3G, 13-city performance tests are to be believed, AT&T’s investment in their network just might be starting to pay off:

84% better download speeds than 8 months ago

64% faster than Sprint, T-Mobile, and Verizon

Average download speed of 1410kps

3x faster in Chicago, 40% faster in San Francisco

94% connection reliability (up from 68% last spring)

iPhone on AT&T had the fastest downstream/upstream performance of any smartphone/network combo (worst was Verizon/Droid)

The representative cities chosen for the test were Baltimore, Boston, Chicago, Denver, New Orleans, New York City, Orlando, Phoenix, Portland, San Diego, San Francisco, San Jose, and Seattle.

Here’s hoping AT&T can keep it up, what with those sweet iPad data deals, and most likely a 4th gen iPhone heading their way this summer. For now, though, let us know how fast and reliable your iPhone on AT&T has been lately…

Technorati Tags: att, fastest network, iphone, pc world