When I built my Mac Pro 3,1 machine (Early 2008) back in the day, I chose not to get an Airport Extreme card since I only intended to connect it via an Ethernet cable. However, I've noticed that the new Yosemite Handoff feature apparently requires not only Bluetooth 4.0 but also 802.11ac. There is some debate on the web as to whether just getting USB dongles will work, but I figure it is worth seeing if any official products exist seeing how the mini-PCI port used for the Airport Extreme seems to have been used across several models of Macs.
Is there an 802.11ac Airport Extreme adapter on the market that would work in an old Mac Pro like the macpro3,1? The purpose is to enable Handoff, nothing more.