PCWorld has performed a nationwide "speed showdown" between the four major US carriers to determine which is the fastest for 3G and 4G mobile internet. The publication ran speed tests at multiple locations in over 13 cities including New York, Los Angeles, and Chicago, providing a snapshot estimation of how well each network performed. The good news is that every carrier is offering faster speeds than last year, but which is the fastest?

AT&T was the clear winner for 4G download speeds, averaging at 9.12Mbps in over 11 locations, closely followed by Verizon's LTE service at 7.35Mbps, and T-Mobile's HSPA+42 at 5.53Mbps. In the 4G upload test, Verizon just edged AT&T at 5.86Mbps compared to 4.91Mbps, while T-Mobile were way behind at 1.32Mbps.

When it came to 3G, however, there was no beating T-Mobile. The carrier's HSPA+21 service averaged 3.84Mbps down and 1.44Mbps up, which was head and shoulders above the rest. But what of Sprint, America's "favorite 4G network"? Its 3G and 4G (WiMAX) services propped up the bottom of the table in every test. Sprint's outgoing WiMAX service managed a meagre 2.81Mbps down and 0.97Mbps up, less than T-Mobile's 3G results, giving (a tiny bit of) credence to the claims that HSPA+ should be counted as 4G (it shouldn't). Sprint hopes that its new LTE network will fix the current discrepancies as it's due to start rolling out soon, and should cover 250 million people by the end of 2013. You can find a detailed breakdown of each carrier's results at the source link below.