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Wireless networking is speeding up again--and splintering. In the past year, an abundance of new products that use innovative antenna technologies have delivered significant speed and coverage gains over standard 802.11a, b, and g networking components. These improvements should delight people who routinely move large files within a local area network or those who experience dead spots or inadequate range with their current setups.

As a group, the new antenna technologies are known as MIMO--multiple in, multiple out--because products based on them increase their throughput and range by using multiple smart antennas to optimize transmissions depending on the location of client devices. By contrast, older Wi-Fi products generally transmit signals in all directions, regardless of where those signals are received. Vendors of MIMO products make extravagant claims regarding performance.

Improvements, with theoretical maximum data rates of 108 megabits per second. In practice, data rates are likely to be much lower--but still faster than those of previous enhanced 802.11g products that similarly claimed 108-mbps theoretical maximums.

We tested five MIMO product combos--routers with their corresponding PC Cards--that use one of three competing technologies. Belkin's Wireless Pre-N, Linksys's Wireless-G Broadband with SRX, and Netgear's Pre-N all use Airgo Networks' True MIMO technology. Netgear's RangeMax line uses Video54's BeamFlex antenna technology with the Atheros Super G Wi-Fi chip that powered the enhanced 802.11g products we looked at in our November 2004 story "The Ultimate Wireless Guide". D-Link's Super G MIMO line uses the Super G chip, too, but in concert with Atheros's Smart Antenna technology. (For more about how these versions of MIMO differ, see "Inside the New MIMO Technologies" in this article.)

To establish a baseline for comparison, we tested a sixth product combo that uses no MIMO technology at all. Instead, U.S. Robotics' relatively new Wireless MaxG router and PC Card package relies on less-expensive enhancements such as increased signal strength and more sensitive receivers.

To see how fast and how far these products could go, we ran tests at close, middle, and long range in a house in a neighborhood that had no other detectable Wi-Fi network. We also ran the short-range tests with a standard 802.11g client on the network to measure this client's impact on performance--a likely scenario, as many people's MIMO networks will still contain some standard Wi-Fi devices.

Our tests revealed that no single product--or type of MIMO--consistently outshone the others. In fact, the winner of our close-range and midrange tests was the non-MIMO U.S. Robotics line. MIMO excelled, however, in our long-range tests, which the U.S. Robotics products couldn't even complete. At long range, the best performers were the Airgo-based Belkin, Linksys, and Netgear combos. These results suggest that people who are interested primarily in speed over short distances can safely stick with a non-MIMO network. But for better range and coverage than today's existing 802.11g networks can provide, MIMO products deliver. Factoring in other product attributes--including price, features, and technical support policies--we gave our Best Buy award to Belkin's Wireless Pre-N product combo.

In this article:

• The Realities of MIMO
• Test Results
• How They Work: Inside the New MIMO Technologies
• The User Experience
• Standards: Wi-Fi Security Options
• See our Chart: Pricey Linksys Wins for Setup, Performance