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While some people are still moseying along with poky old 11-megabits-per-second 802.11b Wi-Fi network cards and routers, the second generation of 802.11g is already here, promising rip-roaring speeds of 108 mbps to 125 mbps.

My informal testing shows that the real-world throughput of these souped-up devices is actually more like 22 to 24 mbps, still significantly faster than the real-world speed of 18 mbps you get with basic 54-mbps 802.11g cards.

The catch with all of this is that the "high-speed" wireless mode is nonstandard: In order to get the promised speed increases, you have to use both cards and routers that have the same type of speed-boosting technology, currently selling in two competing flavors: 108 mbps and 125 mbps. The 108-mbps Super G technology, which came out last fall, is based on Atheros chip sets and is used by D-Link and NetGear, among others. The 125-mbps Afterburner technology, which shipped this spring, is based on Broadcom chip sets and is found in products from Belkin, Buffalo, Linksys, and U.S. Robotics, among others.

I tried three of these new high-speed routers (and their companion adapters) to see how they stacked up: Buffalo Technology's AirStation 125 High-Speed Mode Wireless Cable/DSL Router with AOSS (WHR3-G54); Cisco Systems' Linksys Wireless-G Router with SpeedBooster; and D-Link Systems' AirPlus XtremeG DI-624.

Work Together?

Though all these devices are certified Wi-Fi G compatible, that simply means they will perform in the standard 54-mbps 802.11g mode with G cards and routers from other vendors. So if you have a network with a 108-mbps card and a 125-mbps router, the whole thing will run at a maximum of 54 mbps, negating the advantages of the speed-boosting technologies. Similarly, if you have a mixed network of high-speed and regular 802.11g devices, performance will drop when the regular devices are connected.

However, if you are just setting up a wireless home network and can buy matching equipment, either of these technologies will do the job about 33 percent faster than basic 802.11g equipment--but you will be paying about 30 percent more money.

Just how do the Super G and Afterburner modes work? Super G gets part of its speed increase from "bonding" data from two nonoverlapping wireless channels together (normal Wi-Fi uses only 1 out of the 11 channels in the 2.4-GHz range). This channel bonding, though, increases the potential for troublesome interference with microwave ovens, with cell phones, and with other Wi-Fi networks.

Bandwidth Hog?

In particular, Super G has been criticized in the past for using so much of the Wi-Fi band that other networks in the vicinity, which normally would automatically seek out and use nonoverlapping channels to avoid interference problems, could be severely impacted. During my week of tests, I experienced no noticeable drop in performance in either network when I used the D-Link 108-mbps router in the same house with the Linksys 125-mbps router.

In contrast, the 125-mbps Afterburner technology uses just one channel. Instead of bonding two channels of data together, it squeezes more data through a single channel by reducing overhead, and also by aggregrating smaller packets of data into larger ones. Some of this technology will be used in the upcoming 802.11e wireless multimedia enhancements standard, which is designed to improve delivery of streaming audio and video.

The 125-mbps Afterburner vendors claim that their products are all interoperable in high-speed mode, while Super G products may not be. In a separate test, I found that D-Link and NetGear Super G products were in fact compatible in the 108-mbps mode; however, such compatibility may not be true of products from all Super G vendors.

In my informal tests of file transfers from a local server to a wireless client--performed with encryption off, 4 feet from the router, and in 802.11g-only mode--the two technologies provided similar real-world performance, ranging from 22 to 24 mbps in wireless throughput. That's still significantly slower than their 108-mbps and 125-mbps monikers would lead you to believe. Nevertheless, both models boost speeds well above the 802.11g rate of 18 mbps and the 802.11b rate of about 4.5 mbps I achieved with the same test procedure, and they can be a boon to users who need to transfer large files from one computer to another wirelessly or to stream high-quality multimedia files. Just surfing the Internet? Most broadband services connect at well under 1 mbps, so even using enhanced wireless equipment, you won't experience faster performance.

All three shipping routers were easy to connect to the Internet, and all of them have very good router and firewall features, such as MAC address filtering and WPA (Wi-Fi Protected Access) encryption. The D-Link and Buffalo routers also include WDS (wireless distribution system), a convenient way to link multiple routers wirelessly to cover a larger area; for households with children, the Linksys router offers a fee-based parental control system.

The Linksys also had the best setup utility and documentation. However, all three routers and adapters were difficult to get working together in high-speed mode--I fiddled for hours with advanced router settings and card drivers before I got them humming at their top speeds. The job would have taken only a few minutes had better setup utilities been provided. I suspect that many users, after paying the considerable price premium, will simply get the routers working and will never know that the products are not performing in high-speed mode.

Such users should probably not be buying these routers in the first place, though. If all you need is reliable and compatible Wi-Fi service for typical broadband connections, an inexpensive 802.11g router will provide all the speed you require. But if you really need the performance boost that these new routers provide, then by all means step up.