On the plus side, Airgo's ACE technology really does deliver (just barely) over 100Mbps of real, usable throughput. And while it didn't connect in all of my test locations with its default settings, a simple setting change provided over 20Mbps of average throughput in my toughest test location. Truly impressive!
But this test of the RangeMax 240 has also provided a glimpse into the future of high speed wireless LANs and, at least in its present form, it doesn't look good for owners of existing 802.11b and g equipment. While Airgo's technology continues to impress for its abilty to connect with a range of legacy 11b and g adapters, once those adapters join an Airgo-based WLAN, all clients will take a throughput hit that will leave a lot of bandwidth unused.
And if that's not bad enough, the situation looks even worse for owners of legacy 2.4GHz gear when an ACE-based WLAN sets up shop within range. The current ACE interference-avoidance mechanisms appear to be broken in the RangeMax 240 products on the shelves today and I see no evidence that says the Linksys SRX400 gear is in any better shape.
The result is that with default settings, Airgo ACE-based gear hogs as much spectrum as gear with Atheros' Super G inside, and depending on how close the two WLANs are, legacy gear can be essentially knocked off the air. And even when the kinks are worked out, there is no way that an 802.11n WLAN will be able to avoid interfering with a neighboring 802.11b/g wireless LAN parked on Channel 6 without dropping back to using a 20MHz channel, which will also drop its throughput by about half.
Lest you think I'm laying all of this at Airgo's feet, you should remember back to a few years ago when Airgo strongly argued against the use of a 40MHz channel, citing the very interference issues that I've detailed. But the Intel-driven forces eventually got their way and the 40MHz channel is now a reality that all 11n technologists must deal with.
Regardless of the recent peace-making among the warring 802.11n factions that resulted the first 802.11n draft spec, 802.11n still has a long road to travel before it's fully-baked. I hope that some of the compatibility and interference issues that I've described will be addressed in the final spec. But if history serves, I suspect the focus will be more on maximizing 11n performance, leaving consumers with little choice but to upgrade when 11n gear moves into the neighborhood.