Verizon iPhone versus AT&T iPhone: CNET's data winner is... (video)

(Credit: CNET)

Faster, sexier, more reliable signal. That's the hype propping up the Apple iPhone 4 for Verizon at the expense of rival carrier AT&T. But is the iPhone really that much better on Verizon than on AT&T? The answer so far: absolutely.
To test the phones, CNET Senior Editor Kent German and I traipsed all over San Francisco to conduct our field testing showdown between the AT&T and Verizon iPhones. We compared signal strength, upload and download speeds, and load times between the iPhones on the two networks.
In addition to the results below, you can also check out more connectivity tests, and this roundup of all things Verizon iPhone.

The tests

We ran four tests each in four locations that have given us trouble in the past on multiple networks.
First, we checked the number of bars that appeared in the signal meter. We know that bars are an arbitrary measurement because they fluctuate so often and don't always translate into real-world connectivity. Still, for many people they are a key indicator of service.
Next, we used the Root Metrics iPhone App to measure signal strength and upload and download speeds. Third, we uploaded a photo to Facebook--the same picture for each round for both phones. Lastly, we loaded the GiantBomb.com Web site.

Comparing data speeds on the iPhone 4 (photos)

The locations

CNET's garage served as the first location, a natural fit since the above-ground parking lot is constructed from thick, signal-blocking concrete. Next we drove over to Treasure Island, a slug of man-shaped landfill mounds in the middle of the San Francisco Bay that's removed from clusters of cell towers. Next we stopped on a busy downtown street in the Financial District, where tall buildings and throngs of smartphone users add up to often iffy service. Finally, we climbed into the Twin Peaks neighborhood, a high roost that's home to a dead zone for multiple carriers that's confounded Kent time and again.

How they fared

And the winner is...

	CNET GARAGE	TREASURE ISLAND	FINANCIAL DISTRICT	TWIN PEAKS
Download/Upload	Verizon	Verizon	Verizon	Verizon
Photo uploading	Verizon	Verizon	Verizon	AT&T
Load a Web site	Verizon	AT&T	Verizon	Verizon

*We omitted the "bars" test because that indicator doesn't reflect performance testing.
Verizon devotees scored big points as the iPhone on its network consistently outperformed the AT&T iPhone in all but two tests.
However, before you fly Big Red's banner, keep in mind that these results are indicative of our particular experience. Results in your area may differ, and they may also change over time. Although AT&T's HSPA 3G network is technically faster than Verizon's EV-DO, the results don't always align. Coverage depends heavily on your exact location and even the time of day.
Additionally, Verizon was supporting very few iPhones at the time we tested the phone--performance factors could very well change in San Francisco as well once the number of iPhone users grows on Verizon's network. Yes, there are other smartphones on both networks that impact data load, but Verizon could be gaining a much hiegher percentage of high-data users in the near future if new customers flock to the iPhone--either because they're switching from another network or because they're switching from a feature phone. Either way, we plan to revisit testing in several months when there are more Verizon iPhones on the market.

The detailed results

iPhone versus iPhone

	CNET GARAGE	TREASURE ISLAND	FINANCIAL DISTRICT	TWIN PEAKS
Test 1: Number of bars
AT&T	4-5	4-5	5	1-5
Verizon	5	4-5	5	2-5
Test 2: Download/upload speeds*
AT&T	Download: 40Kbps Upload: 28 Kbps	Download: 189Kbps Upload: 24 Kbps	Download: 116Kbps Upload: 173 Kbps	Download: 120Kbps Upload: 130 Kbps
Verizon	Download: 518Kbps Upload: 149 Kbps	Download: 440Kbps Upload: 66 Kbps	Download: 651Kbps Upload: 55 Kbps	Download: 543Kbps Upload: 174 Kbps
Test 3: Photo uploading
AT&T	12 seconds	28 seconds	15 seconds	4 seconds
Verizon	8 seconds	9 seconds	8 seconds	5 seconds
Test 4: Loading a Web site
AT&T	33 seconds	28 seconds	17 seconds	12 seconds
Verizon	10 seconds	66 seconds	12 seconds	11 seconds

*Measurements taken from Root Metrics test. As we mentioned, AT&T bested Verizon in just two of our iPhone tests--loading a Web site faster at Treasure Island (the Verizon iPhone hung for over a minute) and uploading a photo to Facebook from our Twin Peaks test spot. In all other tests, Verizon came out ahead, but not always by much.
Verizon blazed through AT&T's upload and download speeds, according to the Root Metrics tool, with the largest performance chasm taking place in CNET's garage. But more important than the results of a diagnostic tool are the real-world upload and download speeds we conducted using Facebook and Giantbomb.com, and in these tests AT&T's iPhone fell less behind.