A recent set of tests show that AT&T really is the faster iPhone network, but Verizon beats it for reliability. The tests also show that T-Mobile can offer speeds comparable to AT&T.
The testing was done by Seattle-based firm Ookla, which does network tests on broadband systems using Speedtest.net. Looking at thousands of devices, Ookla tested the AT&T network on an iPhone and compared it to the speeds obtained on Verizon. The result was that AT&T averaged 1,790 kilobytes per second download speeds, against Verizon's 848. Upload speeds were 730 kbps and 506 kbps, respectively.
The difference is reflected in the advertising: Verizon has focused on the extent of its network, whereas AT&T has played up the speed.
While the difference in speed between Verizon and AT&T looks stark, Ookla co-founder Doug Suttles noted that a jailbroken iPhone (something that is legal to do, though it voids the warrantee) might do just as well on another network. T-Mobile in the U.S., for example, showed download speeds of 1,670 kbps, and upload speeds of 518 kbps.
He added that Verizon's LTE network could well be faster than AT&T's, though one would need to be using an LTE-capable device. The iPhone is not one of them.
iPhones on European networks can often do better. An iPhone bought in Switzerland on Swisscom's network will pull down data at 2,122 kbps and upload it 528. In Turkey, the upload speed is 2,487 kbps and uploads of 1,440.
Tests were performed during the week of Feb. 8-15. The download speed was measured by downloading small files to the client device, and sampling the throughput every thirtieth of a second. The samples are then aggregated and the fastest 10 percent and slowest 30 percent are discarded. The remaining slices then can be averaged to get an estimate of download speeds. A similar method was used to test upload rates. Ookla also tested latency (the time it takes to get a response from a server on the Internet). Suttles said the speed tests don't provide a good way to test for how robust a network is as data transmissions won't register dropped calls the way a voice transmission does.
Other testers (notably Engadget) looked at the rate of dropped calls. When the iPhone 4 was first rolled out there were customer complaints that the calls dropped often and that holding the phone a certain way would block the signal. While Apple never formally admitted there was a problem, a number of blogs and news outlets said the problem was that the antenna was on the outside of the phone, and designed in such a way that when a user touches it there are signal problems.
The Verizon iPhone has a slightly different antenna design, in part due to running on a different network. While there are still reports of signal problems, they don't seem as widespread or severe. Despite the problems, Verizon was given higher marks for reliability, despite the slower download speeds.
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