May 21, 2013, 9:39 PM — As much as we hear about LTE service these days, the fact is that three-quarters of U.S. wireless subscribers still use good old 3G service. For AT&T and T-Mobile, that means HSPA service (although the companies call it "4G"), while for Sprint and Verizon that means CDMA service.
In recent years, all of the major wireless carriers have faced a significant challenge in funding the build-out of their new LTE networks while reserving enough to pay for the upkeep of their existing 3G networks. Such maintenance is important for keeping 3G smartphone users connected to the Web, of course, but it's also critical because all of the carriers still run their voice services over their legacy 3G networks. The migration of voice services to the LTE networks is still years away; when that happens, voice will become an all-IP service (VoIP).
Overall, our tests show that HSPA (T-Mobile and AT&T) service is continuing to outpace CDMA service (Verizon and Sprint) in raw network speed.
T-Mobile's HSPA 14.4 service registered scores of as high as 11.54 megabits per second for downloads, but also had scores as low as 0.02 mbps. AT&T's service was a bit more consistent, hitting in the range of 2 mbps to 4 mbps in most of our test cities. Overall, the average speeds for both carriers rose considerably from last year. (See the chart below.)
The speeds of the CDMA data services from Verizon and Sprint each retreated slightly in this year's tests, as the average speeds for Verizon and Sprint 3G both sat well below 1 mbps. Meanwhile, the average scores of the HSPA services in our tests were at least three times faster than that.
The difference in 3G scores can matter a lot, even if you have a 4G phone. That's because the voice service in your phone runs over the 3G network, and because the phone will almost certainly downshift to 3G service when the 4G signal isn't available.
To evaluate the real-world speeds of the 3G networks, we tested them using an iPhone 4S at ten locations in each of 20 cities. They include Ann Arbor (Michigan), Atlanta, Boston, Chicago, Dallas, Denver, Houston, Kansas City (Missouri), Las Vegas, Los Angeles, Miami, New Orleans, New York, Omaha, Phoenix, Philadelphia, San Diego, San Francisco, San Jose (California), Seattle, and Washington, D.C.
We performed hundreds of tests of each major national carrier's 3G service at each testing location, and then averaged the results to derive an average speed for each city. We then averaged the average city speeds to derive a "national" average speed.