With all the hubbub surrounding "4G," it's a valid question to ask which next-generation flavor is actually providing faster speeds to mobile customers. A report published yesterday at PC World attempted to do just that.

The study involved the four major national carriers (AT&T, Sprint, T-Mobile and Verizon) in 260 locations spread among 13 U.S. cities. PC World found what it called "clear winners and losers," as well as some "good news about wireless service in the United States as a whole," specifically that average speeds have increased dramatically across the board since the same time last year.

Verizon's LTE network managed the fastest average speeds for laptops, but T-Mobile took home the gold when it came to smartphones. According to the report, Verizon's network had an average download speed of roughly 6.5 Mbps and an average upload speed of 5 Mbps for laptops. Those speeds were followed by T-Mobile, which trailed with 2.83 Mbps download and 0.85 Mbps upload.

Conversely, T-Mobile's smartphones running on that carrier's HSPA+ network emerged equally as far out in front of the pack as did Verizon's laptops on LTE. The T-Mobile HTC G2 saw average download speeds of almost 2.3 mbps, nearly 52 percent faster than the second-fastest phone, Sprint's HTC EVO 4G, which had an average download speed of 1.5 Mbps.

It's worth noting that Verizon Wireless' first LTE-capable smartphone, the HTC ThunderBolt, has yet to be released (March 17) and was not included in PC World's testing.

AT&T, which was the leader in last year's January 2010 survey, increased speeds over last year, but fell off some relative to other carriers this year. AT&T's average download speeds in laptop-modem tests grew 76 percent to a roughly 2.5 mbps average this year. But each of its competitors showed bigger jumps in download speeds over the past year, resulting in a third-place finish for AT&T in this year's speed results.