( WIRED ) -- For downloading data , the Verizon iPhone is slower than the AT & T iPhone , and it 's also slower than most other Verizon smartphones , according to a study published Monday . Mobile analysis firm Metrico performed a comprehensive study on several AT & T and Verizon handsets , including the iPhone on both networks . The data suggests the differences between AT & T and Verizon are greater than we initially thought . The debut of the iPhone on Verizon sheds light on more subtle differences between the Verizon and AT & T networks . Now that both networks have the same data-intensive iPhone capable of performing identical tests , it 's been easier for researchers to collect more comparable data . Independent tests by multiple publications , including Wired.com , have found that AT & T 's network is faster , while Verizon 's is more reliable with phone calls . Metrico 's tests paint a conflicting picture . Some of their findings : . -- The Verizon iPhone performed `` below average '' in data download speeds when compared to other Verizon phones including the HTC Incredible . -- For voice calls , the Verizon iPhone was one of the highest ranked in noise-canceling performance and was an average performer in voice quality . -- The AT & T iPhone was the top performer in data transfer rates , but it ranks lower in call performance and Bluetooth speech quality compared to some BlackBerry , HTC and Samsung phones . -- The AT & T iPhone completed 10 % more download sessions than the Verizon iPhone when the handsets were moving in a car , for instance . -- But the Verizon iPhone had a 10 % better success rate when uploading data in a stationary environment , like sitting at your desk . The rest of Metrico 's results tell the story we 've already heard : The AT & T iPhone 's download speeds are about double the mean download speed of Verizon 's . However , even though AT & T 's iPhone downloaded files faster , when it comes to loading web pages , the average load time is about the same on both devices , Metrico added . Metrico explained that many different factors affect web performance , including network latency and the operating system 's rendering times . ( Indeed , a previous bandwidth test performed by Speedtest.net found that both the Verizon and AT & T iPhones turned in the same average latency times of about 350 milliseconds . ) Most peculiar to Wired.com is that the Verizon iPhone is `` below average '' in download speeds compared to other Verizon handsets . Was the handset purposely slowed down to avoid overloading Verizon 's network ? Is there something about Apple 's hardware that makes it slower than other handset makers ? It 's tough to say : Metrico does n't have theories to explain the test results . `` I ca n't say it 's related to technology at this point , '' said Rich McNally , vice president of information product at Metrico . `` We 're measuring what happened , not necessarily why . '' To perform the study , Metrico put each phone through live tests on the AT & T or Verizon networks , as well as Metrico 's own simulated network . On the simulated network , the phones completed tests and transferred data to Metrico 's servers for more consistent , controlled results . The phones were also tested in both stationary and mobile environments . For mobile testing , the phones were tested inside automobiles while driving . In all , the company performed more than 10,000 web page downloads , 2,000 data download/upload tests , and 4,000 voice calls . Subscribe to WIRED magazine for less than $ 1 an issue and get a FREE GIFT ! Click here ! Copyright 2010 Wired.com .
AT iPhone network is faster , while iPhone 's is more reliable with phone calls . The AT & T & T 's 's download speeds are about double the speed of Verizon 's . the Verizon iPhone had a 10 % better success rate when uploading data when sitting still .