Apple today released Wi-Fi Update 1.0, which corrects problems that can occur when using the 5 GHz band for Wi-Fi connections.
Most Wi-Fi routers and access points, including Apple's, support both the 2.4 GHz band used in the original 802.11b Wi-Fi specification and the 5 GHz band that was part of the original 802.11a specification. Both Wi-Fi bands are used in the current versions of Apple's AirPort routers as well as in all current Macs.
The 5 GHz band can be a useful choice if the 2.4 GHz band is already crowded with competing signals from nearby Wi-Fi routers or wireless phones. Some appliances can also generate a good deal of noise in the 2.4 GHz band.
The Wi-Fi 1.0 update fixes compatibility issues between the Mac's Wi-Fi capabilities and a wireless router or access point.
The update is available directly from Apple's web site and requires OS X 10.8.2 or later. You only need this update if you have a 2012 Mac.