Top Speed From T-Mobile's New Network T-Mobile has made so much noise with its new no-contract price plan, it is easy to overlook its addition of LTE service - a faster kind of network - in Baltimore, Washington, Houston, Kansas City, Las Vegas, Phoenix and San Jose. It puts T-Mobile head-to-head with AT&T, which the independent testing company RootMetrics found to have the fastest LTE network in a recent report. T-Mobile was the only major carrier not to have LTE at that time. Since I'm in an LTE market, I took an AT&T LTE iPhone 5 and a T-Mobile LTE iPhone 5 and compared network speed. Using the Speedtest app from Ookla, which records how quickly data moves across a network, I pinged a Washington server repeatedly and averaged the results. Before I give you the outcome, let me point out that this is a highly unscientific test. All of my samples come from a single location. All were tested in a short time. And a lot of factors affect network speed, including how many people are on at a given time. Since T-Mobile's LTE service is new, you can bet there isn't a lot of competition for the signal. With those caveats, I can tell you that T-Mobile was much faster than AT&T - more than twice as fast. AT&T averaged a download speed of 5.8 Mbps, while T-Mobile achieved 12.7 Mbps. It is impossible to know whether T-Mobile will maintain those speeds when there are more people on the network. I can say that AT&T's fastest download nearly rivaled T-Mobile at 12.82 Mbps, but other times fell as low as 3.83 Mbps. The T-Mobile speeds were much more consistent. Also keep in mind that T-Mobile still offers LTE in only seven cities. AT&T has the largest LTE network nationally. If you want a fast phone and are usually in one of T-Mobile's seven LTE cities, it's certainly worth a look. But conduct your own tests. Although networks are nationwide, network performance is very local.