As Verizon Wireless (NYSE:VZ, NYSE:VOD) and AT&T (NYSE:T) argue on TV whose network is fastest and most ubiquitous, independent performance testing firm Root Wireless has put their claims to the test, mapping out the performance metrics of all of the big four’s 3G networks in seven major metro markets. The findings were surprising. Though AT&T has taken a huge public relations hit for poor coverage and capacity on its high-speed packet access (HSPA) network, Root found that it’s network performed best in almost every single category from average download speed to level of connection failure (See TelephonyOnline’s related analysis of AT&T and Verizon’s networks). Root’s complete market data can be seen after the break.

All four operators, however, had their strengths and weaknesses. Sprint (NYSE:S) has the highest coverage networks on the books: typically 90% of its footprint receives receives signals of 50% or greater of full strength. But Root found that Sprint also had the highest data connection failure rate, as high as 15% in Seattle, while the rest of the operators kept their failure rates well below 5%. So while Sprint 3G customers are getting more bars consistently, they’re much less likely to actually complete a data session.

Though T-Mobile (NYSE: DT) was the last to deploy its 3G network, it has managed to build up coverage quite quickly. In five of the seven markets Root tested, T-Mobile’s 3G build out is comparable to its three competitors’. Only in Seattle and San Francisco does it significantly lag the others–surprising considering T-Mobile USA is headquartered in Seattle. Also, though T-Mobile’s HSPA network is much newer than AT&T’s–Cingular was the first operator in the world to deploy HSPA–it’s still much slower than AT&T’s. In several markets AT&T’s average download speeds were as much as double that of T-Mobile’s.

While AT&T seemed to run away with the prize in most of the performance categories, there was one area where weaknesses in its network design were evident. While AT&T had high signal strength in much of its metro footprint, that signal strength tended to fall off rather rapidly outside of those hotzones. In most markets, 30% to 50% of AT&T’s footprint received half-strength signals or worse, which in part explains many of the lack of coverage and capacity complaints AT&T has received from many of its iPhone customers. And that’s that’s to say nothing of Verizon’s most damaging argument: AT&T doesn’t offer 3G service to 25% of population.

Here are Root’s market-by-market results:

CHICAGO

Network Technology: 3G vs 2.5G
Verizon: 98% runs 3G infrastructure
AT&T: 98%
Sprint: 97%
T-Mobile: 96%

Signal Strength

Verizon:
Percentage of network operating at 75% of full strength or better: 22% of network mapped
50 - 75%: 36%
25 - 50%: 37%
25% or less: 5%

AT&T:
75% or better: 34%
50 - 75%: 16%
25 - 50%: 44%
25% or less: 5%

Sprint:
75% or better: 69%
50 - 75%: 24%
25 - 50%: 5%
25% or less: 2%

T-Mobile:
75% or better: 51%
50 - 75%: 18%
25 - 50%: 27%
25% or less: 4%

Data Speeds: Average Download/Upload speeds

Verizon: 259k/138k
AT&T: 359k/94k
Sprint: 236k/72k
T-Mobile: 167k/106k

Connectivity: Chance of data connection failure

Verizon: 2%
AT&T: 2%
Sprint: 11%
T-Mobile: 4%
DALLAS

Network Technology: 3G vs 2.5G

Verizon: 97% runs 3G infrastructure
AT&T: 99%
Sprint: 98%
T-Mobile: 96%

Signal Strength

Verizon:
75% of full strength or better: 16% of network mapped
50 - 75%: 39%
25 - 50%: 41%
25% or less: 4%

AT&T:
75% or better: 54%
50 - 75%: 17%
25 - 50%: 27%
25% or less: 2%

Sprint:
75% or better: 61%
50 - 75%: 30%
25 - 50%: 7%
25% or less: 2%

T-Mobile:
75% or better: 44%
50 - 75%: 18%
25 - 50%: 35%
25% or less: 3%

Data Speeds

Verizon’s average download/upload speeds: 208k/121k
AT&T: 428k/97k
Sprint: 204k/69k
T-Mobile: 266k/161k

Connectivity

Chance of data connection failure:

Verizon: 2%
AT&T: 1%
Sprint: 11%
T-Mobile: 4%


LOS ANGELES/ORANGE COUNTY

Network Technology: 3G vs 2.5G

Verizon: 97% runs 3G infrastructure
AT&T: 99.99 %
Sprint: 89%
T-Mobile: 93%

Signal Strength

Verizon: Percentage of network operating at:

75% of full strength or better: 21% of network mapped
50 - 75%: 36%
25 - 50%: 33%
25% or less: 10%

AT&T:

75% or better: 33%
50 - 75%: 18%
25 - 50%: 42%
25% or less: 7%

Sprint:

75% or better: 66%
50 - 75%: 26%
25 - 50%: 5%
25% or less: 3%

T-Mobile:

75% or better: 42%
50 - 75%: 20%
25 - 50%: 35%
25% or less: 3%

Data Speeds

Verizon’s average download/upload speeds: 241k/115k
AT&T: 350k/93k
Sprint: 207k/67k
T-Mobile: 188k/119k

Connectivity

Chance of data connection failure:

Verizon: 3%
AT&T: 2%
Sprint: 12%
T-Mobile: 4%


NEW YORK CITY

Network Technology: 3G vs 2.5G

Verizon: 97% runs 3G infrastructure
AT&T: 99%
Sprint: 98%
T-Mobile: 96%

Signal Strength

Verizon: Percentage of network operating at:

75% of full strength or better: 37% of network mapped
50 - 75%: 38%
25 - 50%: 21%
25% or less: 4%

AT&T:

75% or better: 71%
50 - 75%: 16%
25 - 50%: 12%
25% or less: 1%

Sprint:

75% or better: 83%
50 - 75%: 12%
25 - 50%: 4%
25% or less: 1%

T-Mobile:

75% or better: 62%
50 - 75%: 17%
25 - 50%: 20%
25% or less: 1%

Data Speeds

Verizon’s average download/upload speeds: 201k/103k
AT&T: 246k/131k
Sprint: 176k/59k
T-Mobile: 198k/119k

Connectivity

Chance of data connection failure:

Verizon: 2%
AT&T: 1%
Sprint: 12%
T-Mobile: 5%


SEATTLE/TACOMA

Network Technology: 3G vs 2.5G

Verizon: 94% runs 3G infrastructure
AT&T: 98%
Sprint: 93%
T-Mobile: 65%

Signal Strength

Verizon: Percentage of network operating at:

75% of full strength or better: 22% of network mapped
50 - 75%: 33%
25 - 50%: 31%
25% or less: 14%

AT&T:

75% or better: 46%
50 – 75%: 19%
25 - 50%: 31%
25% or less: 4%

Sprint:

75% or better: 60%
50 - 75%: 30%
25 - 50%: 7%
25% or less: 3%

T-Mobile:

75% or better: 42%
50 - 75%: 20%
25 - 50%: 33%
25% or less: 5%

Data Speeds

Verizon’s average download/upload speeds: 195k/103k
AT&T: 350k/126k
Sprint: 205k/68k
T-Mobile: 251k/148k

Connectivity

Chance of data connection failure:

Verizon: 3%
AT&T: 3%
Sprint: 15%
T-Mobile: 3%


SAN FRANCISCO BAY REGION

Network Technology: 3G vs 2.5G

Verizon: 96% runs 3G infrastructure
AT&T: 93%
Sprint: 91%
T-Mobile: 68%

Signal Strength

Verizon: Percentage of network operating at:

75% of full strength or better: 30% of network mapped
50 - 75%: 32%
25 - 50%: 31%
25% or less: 6%

AT&T:

75% or better: 33%
50 - 75%: 18%
25 - 50%: 40%
25% or less: 9%

Sprint:

75% or better: 68%
50 - 75%: 23%
25 - 50%: 5%
25% or less: 3%

T-Mobile:

75% or better: 38%
50 - 75%: 18%
25 - 50%: 39%
25% or less: 5%

Data Speeds

Verizon’s average download/upload speeds: 259k/138k
AT&T: 359k/94k
Sprint: 236k/72k
T-Mobile: 167k/106k

Connectivity

Chance of data connection failure:

Verizon: 2%
AT&T: 2%
Sprint: 11%
T-Mobile: 4%


WASHINGTON, DC

Network Technology: 3G vs 2.5G

Verizon: 97% runs 3G infrastructure
AT&T: 99%
Sprint: 91%
T-Mobile: 82%

Signal Strength

Verizon: Percentage of network operating at:

75% of full strength or better: 17% of network mapped
50 - 75%: 30%
25 - 50%: 39%
25% or less: 14%

AT&T:

75% or better: 46%
50 - 75%: 17%
25 - 50%: 32%
25% or less: 5%

Sprint:

75% or better: 63%
50 - 75%: 26%
25 - 50%: 7%
25% or less: 3%

T-Mobile:

75% or better: 35%
50 - 75%: 19%
25 - 50%: 41%
25% or less: 5%

Data Speeds

Verizon’s average download/upload speeds: 204k/119k
AT&T: 308k/135k
Sprint: 192k/60k
T-Mobile: 201k/116k

Connectivity

Chance of data connection failure:

Verizon: 2%
AT&T: 2%
Sprint: 12%
T-Mobile: 2%

AT&T says it has worked hard to improve its much-maligned 3G network over the last eight months--erecting hundreds of new cell towers, using better-performing wireless spectrum, and souping up its cell sites across the country--and the results of our latest 13-city 3G network performance tests suggest that the network has indeed undergone a drastic makeover.

After registering the lowest average download speeds in our 3G performance tests last spring, AT&T’s network turned in download speeds that were 84 percent better than the numbers from eight months ago; in our latest tests, AT&T's download speeds were 67 percent faster on average than those of the other three largest U.S. wireless providers--Sprint, T-Mobile, and Verizon.

In our tests last spring, AT&T posted an average download speed of 818 kbps (kilobits per second) across 13 cities. In our tests conducted in December 2009 and January 2010, AT&T’s average download speed increased to 1410 kbps.

AT&T's download speeds in New York City were three times faster in our latest tests than in our tests last spring; in San Francisco, the AT&T's download speeds were 40 percent faster.

The AT&T network’s reliability improved dramatically, too: Last spring, PCWorld testers obtained a usable broadband connection with AT&T only 68 percent of the time. In our latest tests, testers connected to AT&T successfully in 94 percent of their attempts.