updated 01:00 pm EDT, Tue May 21, 2013
Possibly compatible with previous models, facilitating third-party upgrades
A new Broadcom chipset spotted on a Chinese website may be a component of future Mac updates, bringing 802.11ac (known as "Gigabit Wi-Fi") and Bluetooth 4.0 to new models on a single chipset. Not only will the chip handle all wireless communication for future Mac models, but the new chip appears -- at first glance -- to be backward compatible with similar parts in recent models, opening up the possibility of aftermarket upgrades.
The board goes under the name of Broadcom BCM94260CD PCI-E, a mini combination of Wi-Fi and Bluetooth. Assuming the connectors are exactly the same, the chip would fit in many recent and current MacBook and iMac models and would make it possible for third-party sellers to offer advanced Wi-Fi and Bluetooth capabilities to some older Macs.
Code supporting 802.11ac has been seen in betas of 10.8.4, the next update to Mountain Lion. The discovery suggests that Apple expects to release updated Macs that support 802.11ac before either the release of 10.8.5 or any future version of OS X. This falls into line with speculation that Apple plans to update the MacBook line on or around the time of the Worldwide Developer Conference.
The 802.11ac standard, which has not yet been ratified but is in a finalized form, offers backward compatibility with previous 802.11 standards while offering better capacity, wider coverage and better power efficiency. The new protocol offers speeds up to 1.3Gbps across three antennas, offering a substantial increase compared to 802.11n's maximum speed of 450Mbps. This in turn would make protocols like AirPlay and AirDrop ubiquitous, and make inter-device communications far faster for purposes like syncing and transfer of files.