Continuing our coverage (see part 1 and part 2) of a seemingly widespread issue where having more than 1GB of RAM in a Mac or PowerBook with an AirPort Extreme card can result in wireless network slowdowns and disconnections, especially during periods of heavy network transfers, we've received numerous notes confirming that dropping to 1 GB of RAM or less resolves the issue, as well as verification for another, less invasive and less detrimental workaround.
The solution (which does not require removal of RAM) for a number readers involves disabling all of the connections except AirPort in the Network pane of System Preferences. This can be done for a single network location, or you can change the setting for all of your locations.
Open System Preferences, and go to the Network pane. Then use the pull-down menu next to the word "Show:" to select Network Port Configurations. Disable any ports that are not AirPort (including Built-in Ethernet, Internal modem, etc.)
Charlie McGrath is one reader who had success with this solution:
"I have a new 12" Aluminum PowerBook with 1.2 GB of RAM. Had the disappearing airport networks issue occur yesterday. Removing RAM really isn't an option, since the only removable chip is the 1GB. I tried the solution of creating an Airport-only location in the Network preference pane. So far (a day and counting of heavy use), I've had no problems."
If you have two or more connection types regularly (for instance, if you use an AirPort connection but sometimes link directly to Ethernet), it is also good practice to place the most often used configuration above the less used configuration so that Mac OS X will recognize and utilize it without waiting. The configurations can be dragged and dropped.
Problem not specific to AirPort hardware A handful of reader reports have indicated that this problem is not specific to Apple's 802.11g (AirPort Extreme) networking hardware, and in fact affects cards from other manufacturers as well.
MacFixIt reader Carsten Gruesse writes:
"The problem also happens when I pull the Aiport Extreme and use a Linksys WPC54G Cardbus card (which also uses the Airport Extreme driver). So it is not a hardware problem with the Airport Extreme Mini-PCI card. (So you don't think my Powerbook is messed up: I'm typing this through a Cisco 340 PCMCIA WLAN card -- no problems whatsoever.) I suspect there is a problem in the Apple Broadcom ('Airport Extreme') driver."