Las Vegas: AT&T delivered an excellent average download rate of 11.15 mbps, the third-highest rate for any carrier in any city. T-Mobile's HSPA+ 21 was the fastest 3G service, though its download average (3.11 mbps) ranked as the lowest city-winning mark for 3G download speed in our study.
Los Angeles: We recorded the fastest average 3G download speeds in our study in Los Angeles, where T-Mobile won with a robust 4.78 mbps. AT&T had the best 4G scores in L.A., although its average download speed of 6.62 mbps was the second-slowest winning download speed in our tests.
New Orleans: T-Mobile's HSPA+ 21 service proved fastest among the 3G field in the Big Easy, with averages of 4.49 mbps for downloads and 1.70 mbps for uploads. Verizon's winning average 4G download speed (8.46 mbps) was the second-highest city score for the service in our tests.
New York: In New York we found a wide gap between the best 3G download average (3.30 mbps for T-Mobile) and the best 4G download average (11.35 mbps for AT&T)--an 8.05-mbps difference.
San Francisco: AT&T posted the best average 4G download speed, producing an impressive 10.71 mbps, while Verizon turned in a solid 8.40-mbps download average. AT&T's 3G service performed very well in San Francisco, delivering the company's second-highest average download rate at 3.47 mbps; but T-Mobile was faster, with downloads averaging 4.08 mbps.
San Jose: Verizon 4G clocked average speeds of 7.66 mbps for downloads and 6.52 mbps for uploads, compared with 4.74 mbps for downloads and 2.5 mbps for uploads from AT&T LTE. T-Mobile delivered a winning average 3G download rate of 4.61 mbps.
Seattle: T-Mobile turned in the top 3G download speeds (averaging 3.87 mbps) in Seattle, while its 4G HSPA+ 42 service generated a surprisingly fast average download speed of 7.46 mbps, the carrier's 13-city high. Verizon posted its best 13-city mark for 4G downloads (10.87 mbps on average), making it easily the fastest 4G service in town.
Washington D.C.: T-Mobile had the fastest average 3G download speeds (4.14 mbps), handily beating AT&T, whose 3G scores in D.C. were the worst from the carrier in our 13 test cities. AT&T, however, won on the 4G side with an average download speed of 8.52 mbps.
For details on how we conducted the testing for our 13-city study, see "Methodology in a Nutshell." And, again, for a close-up look at the individual charts for each city, see our full-page testing locations map.