I have three Macs networked at home through an AirPort Extreme Base Station. The MacBook and Intel iMac communication is as fast as greased lightning, but communication with the 2.1GHz iMac G5 is much slower. With the laptop, Intel iMac, and AirPort Extreme Base Station using 802.11n and the iMac G5 using 802.11g, is there a way to upgrade the older iMac to the faster wireless speed?
Frank Blank

The easiest way to do this is to eschew wireless on the old iMac and run an Ethernet cable from the Base Station to the iMac. Your iMac’s network performance will increase dramatically, and its 802.11g wireless won’t slow down the rest of the network, as happens when you mix these varieties of 802.11.

However, if you don’t feel like completely rearranging your home so that the Base Station and the iMac sit near each other, you can upgrade the iMac to 802.11n, but not internally. Apple’s n-flavoured wireless cards don’t work with older iMacs.

There are ways to add 802.11n to older Macs. If you have a Power Mac, you can use one of its PCI slots in league with an 802.11n PCI adaptor. You can also add an n-flavoured USB adapter or, if you have a 15in or 17in PowerBook, use an 802.11n Cardbus adaptor. Both OWC (eshop.macsales.com) and QuickerTek (www.quickertek.com) make such adaptors.

These wireless devices are compatible only with the 2.4GHz standard. If you use AirPort Utility to set your Base Station to the 802.11n Only (5GHz) radio mode, these cards won’t be able to access it.

Even at 2.4GHz, these devices will speed up networking. We tested the Max-Power USB and Cardbus adaptors on a 1.25GHz PowerBook. Using the built-in AirPort card, copying a 650MB file via an 802.11n-compatible AirPort Extreme took about six minutes. With the MaxPower adapters, it took around three minutes. An Ethernet transfer took just 30 seconds, so if you can, run wire for faster speeds.