AT&T iPhone vs. Verizon iPhone: Which Performs Better?

The AT&T iPhone is twice as fast as the Verizon iPhone in data download speed, and 50 percent faster in upload speed, according to results of a study by Metrico Wireless released today.

“There are differences in the raw speed of moving data around,” says Richard McNally, vice president of information products at Metrico, which measures mobile device performance for wireless carriers and handset makers such as AT&T, Motorola, Nokia, Research in Motion and T-Mobile.

In the head-to-head iPhone comparison, which wasn’t conducted on behalf of any company, Metrico downloaded more than 10,000 Web pages, made nearly 4,000 voice calls and performed more than 2,000 data download and upload tests.

In addition to the data speed advantage, the AT&T iPhone proved slightly more reliable when the phones were in motion. The Verizon iPhone completed 10 percent fewer 5MB downloads than the AT&T iPhone. “If you’re uploading 20 photos to Flickr [from a Verizon iPhone], then maybe there’ll be some headaches where a few photos won’t move,” McNally says.

Oddly, the Verizon iPhone beat the AT&T iPhone in data upload reliability when the phones were stationary. In this scenario, the Verizon iPhone had a 10 percent better success rate at uploading 1MB files. So the message is, if you’re sending email attachments on a Verizon iPhone, you might want to stop walking and hold the iPhone still.

Other findings: The AT&T iPhone ranks below average in Bluetooth speech quality, well behind top performers BlackBerry Torch and BlackBerry Curve. The Verizon iPhone ranks among the leaders (Motorola Droid X and LG Ally) in noise cancelling performance.

“The iPhones seem to be in the middle of the pack relative to other devices on their networks,” McNally says.

In Metrico’s head-to-head comparison, the iPhones were comparable in speech quality. The Verizon iPhone, however, has a really quiet speakerphone, McNally noted.

Despite AT&T iPhone’s huge advantage in data download speed, the Verizon iPhone fared equally well in Web browsing performance. That is, Web page downloading tests didn’t show a big difference between devices. McNally says that’s because many factors contribute to Web page downloading performance, such as latency on the network.

“In Web-browsing performance, we run against a standardized Web page,” McNally says. “We do that so the content doesn’t change and we’re able to control it on our own server. We’re actually getting an apples-to-apples comparison.”

Tom Kaneshige covers Apple and Networking for CIO.com. Follow Tom on Twitter @kaneshige. Follow everything from CIO.com on Twitter @CIOonline and on Facebook. Email Tom at tkanshige@cio.com