Airport Extreme slow Internet download speed

No response as yet but I can add a little further information. Using the tool www.speedtest.net I conducted Internet speed tests from my MacBook Pro and repeated the test following various environmental and configuration changes.

As stated previously download speeds on the MB/AirPort Extreme n-network where the MP is the only node are consistently around five (5) times slower than an XP Pro laptop on my g-network. So here are the non-numerical results of my tests:

Note the AE is practically line-of-site to the MB, no concrete walls intervening, distance about 15 feet. The USR router is channel 9, the AE is channel 1.

1. Set the AE to n-only (5Ghz): No improvement
2. Set the AE to n-only (2.4GHz) : No improvement
3. Set the AE to g-only : No improvement
4. Switch off my cordless phone (reduce potential interference) : no improvement
5. Switch the MB to the USR wireless g network : downloads improve to the same level as the XP Pro machine.

Conclusion: Apple's hardware, firmware of software implementation of wireless on the AE is seriously flawed.
I noted that ping times in the speedtest were 25% higher via the AE, which has a Gigabit wired connection to the USR via the WAN port and is in Bridge mode.

Any ideas?

I found the solution. Purchase NetGear NAS and use it to share iTunes library, stream other media and also use it for Time Machine backups. Works a treat. Cable my apartment using NetGear PowerLine Ethernet over Power adapters. A little pricey but seriously good, consistent performance. Sell Apple Airport Extreme to some poor sap and voila, home networking that works.. for me anyway.