Wireless Performance- more
It's easy to get lost in the data, so let me point out some particular weaknesses in the new Extreme's wireless performance. As previously noted, the Extreme has its 40 MHz channel mode locked out in 2.4 GHz, so you see no results for those tests.
But you may have missed the 0 Mbps results in the 2.4 GHz band, Location F. The Extreme had a tenuous hold on its connection in Location E, which resulted in ~ 1 Mbps of speed. But when I moved to Location F, only about 6 feet away, I wasn't able to get a good enough connection to run the test.
Update 11/13/2009An explanation for the poor 2.4 GHz performance can be found here.
Like all other N products, I wasn't even able to see the 5 GHz radio once I moved beyond test Location D.
Highest 2.4 GHz band throughput for the Extreme was 72.5 Mbps running uplink with 20 MHz channel bandwidth in Location A. Highest 5 GHz band speed was 99.1 Mbps also running uplink, but with 40 MHz channel bandwidth in Location A.
Figure 9 shows the summary plot of IxChariot tests for 2.4 GHz downlink tests with a 20 MHz channel width. Throughput is relatively stable, but with some large dropouts.
Figure 9: Six location wireless throughput - 2.4 GHz, 20 MHz bandwidth
Here are the other composite IxChariot plots if you'd like to look:
Maximum Wireless Performance
I ran the same check used on the WNDR3700 and DIR-825 B1 to see how the Extreme performed when I ran four TCP/IP streams simultaneously on each radio. I set up a second notebook using a NETGEAR WNDA3100v2 client connected to the 5 GHz radio and my standard Intel 5300-equipped notebook connected to the 2.4 GHz radio.
Both clients were in the same room, within 10 feet of the router with the 2.4 GHz radio in the only-available 20 MHz bandwidth mode and the 5 GHz radio set to 40 MHz channel bandwidth mode.
Figure 10 shows that the new Extreme was only able to provide about 100 Mbps of total throughput through both radios running downlink
Figure 10: New Airport Extreme aggregate wireless throughput - downlink
Figure 11 shows the uplink results, with 221 Mbps of aggregate throughput, more than 2X download results. Why the big difference? Beats me.
Figure 11: New Airport Extreme aggregate wireless throughput - uplink
For reference, the WNDR3700 yielded 252 Mbps total downstream and 262 Mbps upstream. So the new Extreme is definitely not best-in-class when it comes to total wireless throughput.
I didn't test the previous, Atheros-based simultaneous dual-band Extreme, so I don't know if my results are indicative of the "50 percent better Wi-Fi performance and up to 25 percent better range than with the previous-generation AirPort Extreme Base Station" that Apple claims for this new version. If they are, then I'm glad I didn't waste my money on that version, although I'm not really pleased that I'm out around $200 (including shipping) for this one.
At any rate, Apple's decision to move to Marvell for the latest version of the Extreme seems to be ill-advised since 2.4 GHz range is lower than other current-generation dual-band routers and total wireless downlink throughput is no match for the NETGEAR WNDR3700. Given that I haven't seen Marvell in any other new N router designs, and Atheros is in so many, including the NETGEAR WNDR3700, I'm at a loss to explain Apple's choice.
But performance aside, the Extreme's routing feature set is pretty poor compared to current-generation products. Port forwarding is limited, triggered forwarding isn't supported, there is no port or keyword filtering and no QoS, automatic or even manual. And I've already pointed out the wireless feature weaknesses, which are just plain annoying and border on the paternalistic.
Finally, I encountered the same problem reported by other Airport owners during testing. I forget exactly when, but at one point, the AirPort Utility was no longer able to find the Extreme during its scan. I tried soft and hard resets, power cycling, and even taking out the battery for awhile to try to clear what ailed it, but to no avail.
I would have tried a firmware download, but a 7.5 download was nowhere to be found on either the supplied CD or Apple's support site. Nor was any indication of a fix for this problem in Apple's online knowledge base. So for the latter part of my testing, I had to use the Utility's Configure Other mode, which wasn't even helpful enough to remember the Airport's IP after I typed it in. Given all of the Extreme's other frustrating "features", this was just icing on the cake.
In sum, there is no reason that I can think of to recommend the new Airport Extreme.