The iPhone 3GS-for-Speedy isn't quite as speedy as we thought.

Upstream, it tops out at 384 kbps, according to report

In a succinct, informative Macworld article, Glenn Fleishman explains why.

Simply put: for pulling down data, the 3GS can use AT&T's newer HSDPA service, at 7.2 Mbps. The corresponding upstream service is HSUPA, at either 1.4 or 1.9 Mbps. AT&T is building out this higher speed network.

But the 3GS can't use the faster upstream service. And why? Fleishman notes the smartphone has a UMTS/HDSPA chip for the cellular connection, the earliest 3G implementation on GSM networks. Maximum rate: 384 kbps.

He includes a link to TesMyiPHone so you can check it out yourself. 

I liked his closing: "But I suppose this offers a new marketing bullet point for a future iPhone model—now, with HSUPA!"

Join the Network World communities on Facebook and LinkedIn to comment on topics that are top of mind.

Copyright © 2009 IDG Communications, Inc.