My apartment has more than a dozen devices that feed off the network: two laptops, a printer, an e-reader, wireless speakers, two smartphones, an iPad and more. Yet getting gadgets to connect to my two-year-old wireless router is a dark art. I can surf the Web on the street in front of my house, yet can’t get a signal sitting in bed. In desperation, I even tried dangling a router—the equipment that takes your Internet connection and shares it with the devices in your home—from the ceiling in an effort to distance it from interfering walls.

Surely, covering a whole apartment is a problem that the decade-old Wi-Fi industry can solve. So I tested four top-of-the-line home wireless routers, each of which features the latest generation dual-band “wireless N” technology designed to increase performance.

The result was disappointing. None of the routers could deliver a 100% consistent wireless experience that could take advantage of the latest technology, like Apple’s AirPlay media-streaming service.

One came close, thanks to a controversial signal-boosting feature that could potentially interrupt my neighbors’ networks: the Netgear WNDR3700, which retails for $169.99. Another, the $179.99 Cisco Linksys E3000, was runner-up in some tests, but still sometimes dropped out when streaming music.

My tests weren’t scientific studies of signal strength and speed. Every home is a different combination of size, building materials and potential competition for precious wireless bandwidth, such as other Wi-Fi networks and cordless phones. Even pets can obstruct signals. Because of that, router manufacturers won’t even offer estimates on the range their devices can serve.

I conducted real-world torture tests designed to see how the routers might perform in challenging scenarios at completing tasks like streaming media to iPhones and moving large files between computers. I didn’t test devices known as repeaters, which extend the range of an existing network, because I wanted to see how far I could push the routers on their own.

My 100-year-old apartment building features materials that act like kryptonite to Wi-Fi signals, such as metal mesh in plaster. Worse, my urban San Francisco building is surrounded by apartments with their own Wi-Fi networks—25, at last count.

For balance, I also tested the same four routers on my friend Mark’s suburban house, which competes with fewer neighboring Wi-Fi networks, but is larger. In our suburban tests, the routers performed in largely the way they did in the urban environment, though in that setting both the Netgear and Cisco performed admirably. A third model, the $109.99 Belkin Play N600HD, performed adequately.

All the routers I tested, which included the $179 Apple Airport Extreme, feature a technology called simultaneous dual band. This means they really run two networks. Devices that need to receive a lot of data, like video, can use the digital equivalent of a carpool lane, while the rest of your data take the regular highway.

That seems like a good idea, but the technology made little impact in my tests, because many devices don’t yet support the new frequency, 5 GHz. The iPad does, but the iPhone 4 does not, and nor did my older H-P laptop. Moreover, 5 GHz comes with a drawback: its signals usually can’t travel as far through walls as the older technology, transmitting at 2.4 GHz.

Rather than overall speed, the biggest Wi-Fi problem I encountered was getting the network to reach the nooks and crannies of the house. To test that, I compared the ability of each router to stream media to a device like my iPhone in trouble spots, such as my dining room or Mark’s patio.

The results were often stark. To Mark’s upstairs bedroom, the Netgear and Cisco routers could stream a video with ease, but the Apple would sometimes slow to a crawl. When I sent a file over the network to that same spot, the Apple router was sometimes one-tenth the speed of the Netgear and Cisco.

In my urban apartment, only the Netgear router was able without interruption to stream music from an iMac to speakers about 50 feet and five walls away. The music would conk out occasionally with the Cisco router, and quite often with the Belkin and Apple.

And even the Netgear would stumble when I tried the latest feature for the iPhone called AirTunes, which lets you stream media from an iPhone or iPad to the Apple AirPort Express or Apple TV. That technology requires the data to take a longer round trip to its final destination, stressing the network further.

With the Netgear router, I experimented with a setting called “performance mode.” Using it significantly improved the reliability of the network in some parts of my apartment, and put Netgear into a higher class.

But that option, which is sometimes called “channel bonding” or “20/40″ mode, is controversial because it essentially pushes signals from your neighbors’ Wi-Fi networks out of the way.

The Wi-Fi Alliance, which certifies Wi-Fi equipment, said it now requires routers to switch to a neighbor-friendly mode if other networks are around—but this Netgear router was certified prior to that rule. The other router makers say they either don’t offer the option, or automatically downscale when there are neighboring networks.

Wi-Fi technology shouldn’t make me have to choose between my neighbors and my network. A Netgear spokesman told me that in my situation, neighbors aren’t likely to feel an impact, because my impenetrable walls keep the signal from traveling very far anyway.

Being a good neighbor aside, I’d recommend either the Netgear or Cisco routers for users looking to cover a tough space—and hope that the networking industry can come up with even better technology soon. In the meantime, moving a router away from objects that can degrade the signal, like mirrors and refrigerators can help. And the desperate can fall back on a wireless repeater.

Apple Airport Extreme, $179
The most pleasing to look at and simple to install, but suffered from slow transfer speeds and frequently struggled to stream music to difficult locations.

Belkin Play N600HD, $109.99
Acceptable and sometimes impressive file transfer speeds, but often dropped the connection while streaming music.

Netgear WNDR3700, $169.99
The least pretty, but most reliable, especially when using the potentially neighbor-unfriendly ‘performance mode.’

Cisco Linksys E3000, $179.99
Fast in most tests, but sometimes cut out when streaming music. A good option for the less technically inclined

Walter S. Mossberg returns next week.

Write to Geoffrey A. Fowler at geoffrey.fowler@wsj.com

This morning Apple (AAPL) refreshed its desktop line, announcing a new Nehalem-based Mac Pro, a more robust Mac mini and four new iMacs, among them, three with 24-inch screens. All three lines boast fundamental enhancements, but also more affordable prices–a feature Apple touted in its marketing materials the way it would a new technology. Consider this pull quote from Apple COO Tim Cook: “Our flagship 24-inch iMac with twice the memory and twice the storage is now available for just $1,499. The Mac mini is not only our most affordable Mac, it’s also the world’s most energy efficient desktop computer.” And this one from Philip Schiller, Apple’s senior vice president of Worldwide Product Marketing: “The new Mac Pro is a significant upgrade and starts at $300 less than before.”

An interesting change from Apple’s standard marketing language, which typically holds its new machines up as “the most incredible desktop computer we’ve ever made” or “our fastest, biggest and brightest” or “the workstation Mac users have been dreaming about.”

These days, Apple’s new Macs are not simply faster and shinier, they’re a bargain as well. “Insanely great!” has become “insanely affordable!” Anyway, on to the specs.

The new Mac Pro is priced at $2,499 for the quad-core version and at $3,299 for the eight-core version, with Nehalem Xeon processors running at 2.93GHz. All feature an updated system architecture that Apple says delivers twice the performance of the previous model.

The new iMac line starts with the 20-inch iMac for $1,199 with a 2.66GHz Intel Core 2 Duo processor, 2GB of 1066 MHz DDR3 memory, a 320GB Serial ATA hard drive and Nvidia GeForce 9400M integrated graphics. Its 24-inch brethren features a 1920-by-1200-pixel widescreen display that offers 30 percent more screen real estate than the 20-inch model. It offers up to a 3.06GHz Intel Core 2 Duo processor and starts at $1,499–the same price as the previous generation 20-inch model.

The new Mac Mini has been outfitted with the same Nvidia GeForce 9400M integrated graphics as Apple’s new MacBooks, something the company says will improve its graphics performance as much as fivefold. Available in two models that start at $599, the mini features a 2GHz Intel Core 2 Duo processor, up to 4GB of DDR3 1066MHz memory, up to 320GB Serial ATA hard drive, five (!) USB 2.0 ports, FireWire 800 and a SuperDrive.

Also receiving a refresh today: Apple’s Time Capsule and AirPort Extreme, which now offer a “guest networking” feature that allows users to create a separate Wi-Fi network just for their friends and supports for simultaneous dual-band Wi-Fi. “For maximum range and compatibility, Time Capsule works simultaneously on both the 2.4GHz and 5GHz bands, allowing all the devices on the network to use the most efficient band automatically,” Apple explains. “And Time Capsule uses the latest 802.11n wireless technology so you can enjoy up to five times the performance and up to twice the range of 802.11g wireless networks.”