AT&T has the fastest iPhone 4S network, Verizon the most reliable

In a smackdown between US cellular carriers AT&T, Sprint and Verizon, which network reigns supreme? That was the question answered by a new report by performance analytics firm Metrico Wireless Inc. that compared the carriers to determine who has the fastest and most reliable network.

To perform the tests, Metrico grabbed more than 21,000 web pages, did over 8,000 speed tests and made more than 6,000 voice calls from the iPhone 4S. The company has a proprietary measurement platform that is used to monitor the performance of the carriers.

The fastest network in the comparison was AT&T, with maximum download speeds of 6,047 Kbps and a mean speed of 3,210 Kbps. Verizon was well behind in the speed race, with a maximum download speed of 2,371 Kbps and a mean of 1,071 Kbps. In other words, the average download speed for AT&T was almost triple that of Verizon. Sprint was even slower, with a maximum speed of 1,767 Kbps and a mean speed of only 581 Kbps.

When it came to call failures, Verizon had the fewest -- only 2.1% of test calls failed. Sprint was the worst network for dropping calls, with 3.7% of calls dropping. AT&T was in the middle with a failure rate of 2.8%.

Metrico also found that the iPhone 4S has an average dropped call rate of about 1.4%, which is poor in comparison with competing smartphones. However, in terms of data task reliability, the iPhone 4S was at or near 100%, making the newest iPhone among the best in the world.