“The AT&T and iPhone combo turned in the fastest average speeds–downstream and upstream–of the four carrier/smartphone combinations we tested, outperforming its rivals in more than three-fourths of the cities we sampled,” PC World explained it its study.

“AT&T connected the iPhone at an average download speed of 1259 kbps, and an average upload speed of 215 kbps over the 13 testing cities,” the study notes. “The iPhone clocked download speeds of at least 1000 kbps in more than 60 percent of our testing locations, with burst rates often exceeding 3000 kbps, and we managed to obtain a reliable connection in 91 percent of our AT&T/iPhone tests.”

The PC World study confirms results of a similar 12-city 3G performance study by Gizmodo last year.

A remarkable improvement, although it should be noted that San Francisco is still plagued by reliability issues. PC World found just 55 percent of connections made on AT&T’s network in the city to be successful. Bay Area users can only hope that the additional cell towers, cell site upgrades and increased back-haul capacity the carrier is said to be rolling out will improve this metric in short order.

PREVIOUSLY:

• AT&T: “We’re Closing the Gap” in New York and San Francisco
• Apple COO: Leave AT&T Alone
• If You Think AT&T Has Network Problems Now, Just You Wait
• AT&T 3G Improving–If You Can Get a Signal
• Admitting You Have a Problem Is the First Step, AT&T
• Usage-Based Data Pricing: The Solution to AT&T’s iPhone Problems?
• AT&T Ranked Last in Consumer Reports’ Best Cellphone Service Survey
• Apple Joins AT&T/Verizon Spat With New iPhone Ads
• AT&T Awarded Hug and a Box of Tissues in Verizon Ad Case
• Time to Cut AT&T Some Slack, iPhone Users?
• Thanks, iPhone: 2,000 Percent Increase in Bay Area Data Traffic Since 2008, Says AT&T
• Verizon to AT&T: Do Yourself a Favor and Shut Up
• Frosty’s Winter Litigation Wonderland: AT&T Demands Verizon Pull Holiday iPhone Ads
• Verizon Banishes iPhone to Island of Misfit Toys
• Verizon on AT&T Suit: There’s a Word for That. “Junk
• Verizon to iPhone Users: “Want Five Times More 3G Coverage? There’s a Map for That.”
• iPhone Owners Would Like to Replace Battery, AT&T

And the cellular broadband services, such as Verizon Wireless’s BroadbandAccess, can operate at speeds roughly equivalent to, and sometimes well beyond, the speed of basic wired home DSL service. That means you can surf the Web, and get email and large attachments pretty efficiently.

The card for the Verizon network

A small percentage of users hook up to these cellular broadband networks using laptops that have the necessary gear built in. Another small group uses a cellphone as a modem. But most users of these networks use external cellular-modem cards that plug into a standard slot on the side of their laptops. Therein lies a problem.

The computer industry is in the process of dumping that standard slot, called a PC Card slot, for a new, incompatible slot called ExpressCard. So, buyers of many new laptops are finding their cellphone modems are obsolete.

Now, Novatel, a leading maker of these cards, has come out with a couple of new ExpressCard versions for cellular broadband networks. One, which works on Verizon Wireless’s network, is already on the market, sold by Verizon and by Dell. The second, which works on Cingular’s BroadbandConnect high-speed network, will go on sale from Dell and possibly Cingular later this year, likely late November.

I have been testing the Verizon version of the card, called the V640, as well as a pre-release model of the version that works with Cingular, which Novatel calls the Merlin XU870. The tests not only gave me a chance to evaluate the cards themselves, but also to compare the Verizon and Cingular high-speed networks.

My verdict: The cards were easy to set up and use, and worked well. But the two high-speed networks are very different. While Cingular gave me higher speeds than Verizon in a couple of locations, the Verizon Wireless BroadbandAccess network crushed Cingular’s BroadbandConnect in most places I compared them.

This wasn’t a rigorous scientific test. I used two different laptops, an Apple MacBook Pro and a Dell Latitude D820. The Cingular tests were all conducted on the Dell, because the Mac software for the Cingular card won’t be ready until the card goes on sale. The Verizon tests were all conducted on the Mac. On both machines, I used the test service at speakeasy.net, accessed via the Firefox Web browser.

Also, I tested the cards in only Washington and New York City, and on Amtrak’s Acela Express trains in between. That is a heavily populated region; it’s also Verizon’s home territory, and Cingular might have done better in other parts of the country. Verizon has been rolling out its high-speed network since 2003; Cingular is well behind. Verizon offers the service in 185 metro areas; Cingular is in just 75.

Both cellphone carriers charge $60 a month for unlimited data service using the cards, if you have a voice plan with them. The new Verizon card costs $180. The new Cingular-compatible card is likely to cost $50 more.

The cards look nearly identical, and each works on both Windows and Macintosh computers. On Windows, you must connect using special software. On the Mac, you can simply use integrated software from Apple, if you choose. Both cards have small flip-up antennas and indicator lights. Both worked fine.

Verizon’s high-speed service is often called EVDO, for its underlying technology. Cingular’s service uses a technology called HSDPA.

In my tests, which involved about 20 head-to-head comparisons, the Verizon card and network averaged 818 kilobits per second “downstream” (to get Web pages, and to receive email and attachments) and 113 kbps “upstream” (to send email and files).

By contrast, the Cingular-compatible card averaged just 463 kbps downstream and 77 kbps upstream. Plus, during the three-hour train trip, Cingular disconnected me, or simply had no coverage at all, eight times. Verizon did so only once. Verizon has a deal with Amtrak that supplies data service inside the trains, which helped, but this in-train signal doesn’t include the high-speed EVDO service.

Cingular did beat Verizon in two places: my hotel in New York’s financial district and my office in downtown Washington. In the hotel, the Cingular service got a downstream speed of 1753 kbps — its highest in my tests — versus 888 kbps for Verizon and just 747 kbps for the hotel’s expensive wired Internet service. In my office, Cingular got 1133 kbps downstream versus 644 kbps for Verizon.

But the downstream speeds varied wildly. In Trenton, N.J., the Cingular service managed just 16 kbps. The best for Verizon was 1366 kbps in New York’s Penn Station, while its worst was 132 kbps between big cities in New Jersey.

I recommend both new cards. But unless you live, work and travel in very strong Cingular coverage areas, Verizon is the better choice for high-speed wireless data, at least today.

Email me at mossberg@wsj.com.

For instance, Verizon’s entry-level DSL service, at 768 kilobits per second for downloads and 128 kilobits per second for uploads, is considered high-speed here. But in Japan and Korea, families can buy moderately priced Internet service measured in the tens of megabits per second. They get a race car, while Americans are stuck with a bicycle.

A megabit per second (mbps) connection moves about 1,000 times as much data every second as a kilobit per second (kbps) connection. A service running at 10 megabits per second is more than 13 times as fast as Verizon’s base DSL service. All such services have two modes: downstream, for downloading Web pages, email and files; and upstream, for uploading email or files. Generally, Internet providers offer much faster downstream speeds than upstream speeds.

Even the faster common U.S. broadband offerings, like Comcast’s $42.95 a month basic cable-modem service, which delivers 6 mbps downstream and 384 kbps upstream, are ridiculously slow compared with the Asian offerings.

But now, Verizon is offering Americans in certain parts of the country a new, much faster Internet service for only a little more than Comcast charges for its basic service. This new product, called Fios, offers 15 mbps downstream and 2 mbps upstream for $50 a month, or $45 a month if you use Verizon for your telephone service.

There are also two other Fios plans: 5 mbps downstream and 2 mbps upstream for $40 a month; and 30 mbps downstream and 5 mbps upstream for $200 a month. Both also are discounted if you also use Verizon phone service.

I had Fios installed in my house in July, and I’ve been comparing it with Comcast’s basic cable-modem service. I have been pleased with Fios’s speed and reliability, which are true to Verizon’s claims. On some tasks, it is markedly faster than Comcast. And on my laptops connected via a Wi-Fi wireless network, which tends to degrade Internet speeds, the speed increase has been especially noticeable.

This speed boost, however, isn’t the kind of transforming event that people experience when they first move from dial-up to broadband; there’s a limit to the discernible speed increase you can get when downloading Web pages and email — the two most common Internet activities.

So far, Fios is available to fewer than three million homes and business in selected cities and towns in just 15 states, including the Maryland suburb of Washington where I live. Soon, Fios will have competition. Comcast has been working on its own higher-speed solution, and I expect Comcast to match or exceed the Fios downstream speed in these parts of the country where Fios is available in the next few months.

I chose the middle of three Fios plans Verizon offers — 15 mbps downstream and 2 mbps upstream. It took two visits from Verizon crews to install my Fios service — one to lay a fiber-optic cable to my house, and another to install the indoor electronic gear. The service hasn’t been down for even a minute since it was turned on.

I ran a rigorous series of tests comparing Fios with the Comcast basic cable-modem service, using an Internet speed test site accessed from a hard-wired Windows PC. My Fios service repeatedly was measured at just over 15 mbps downstream and around 1.8 mbps upstream. The Comcast service clocked in at a mere 2.3 mbps downstream and around 360 kbps upstream.

Comcast says I should have gotten nearly 6 mbps downstream in my tests, and that my poor test results are likely due to some problem unique to my house. But even if I had gotten, say, 5.5 mbps downstream with Comcast, Fios would have still won hands down.

On my Windows and Mac laptops connected wirelessly via Wi-Fi in distant parts of my home, test speeds jumped from under 1 mbps with Comcast to around 8 mbps with Fios, a huge improvement.

I also did some real-world comparisons. I downloaded a 65.8 megabyte file with Fios in just 42 seconds, compared with nearly seven minutes with Comcast. An uploading test was even more impressive. I uploaded five digital photos, totaling 10.2 megabytes in size, to an online photo service. Fios did this job in just over eight minutes, while Comcast took one hour and 22 minutes.

Streaming video clips from the Internet were much smoother, and suffered fewer hiccups, with Fios than they did with Comcast, especially on my wireless laptops. But Fios wasn’t markedly faster at fetching Web sites, or downloading email without large attachments.

I consider Fios a good service and a good bargain. If you are a heavy Internet user, and you can get it, I recommend you do so. That is especially true if you use the Internet over a wireless network, and stream a lot of videos, or download and upload lots of files. If you are a light user, just surfing the Web and doing email, a slower service will do fine.

• Email me at mossberg@wsj.com