We tested under 10.8.4 and 10.8.5 using both the AFP and SMB protocols (AFP is said to be fixed in the 10.8.5 release notes SMB is not mentioned). The laptop is about ten feet from the router, and there is a clear line of sight between the two. The Mac mini is connected directly to our 802.11ac AirPort Extreme Base Station via gigabit Ethernet, while the Air is connected to the AirPort via 802.11ac. Our network configuration remains the same as it was in our original testing: we're copying a single large file from a 2012 Mac mini to a 2013 MacBook Air using the AFP and SMB protocols. 10.8.5 allegedly fixes this issue, so I broke out my 2013 MacBook Air to see what kind of improvements we can actually expect.

Additional testing in Windows 8 confirmed that there was no problem with the hardware-for whatever reason, file transfers under OS X were less than one-third of the speed they were in Windows 8. It was one of the first high-end laptops to ship with support for the faster 802.11ac Wi-Fi standard, but our testing found that the improvements over the 802.11n adapter in the 2012 model just weren't as large as they should have been. One of the fixes included in the update is meant to remedy a problem we had with the 2013 MacBook Air.

You can grab the Combo updater from Apple's support page here or download the update automatically through the App Store's software update page. It's no Mavericks, but as usual the update includes a lengthy list of fixes and security updates that you'll want to apply to any Mac running 10.8. Apple has just issued OS X version 10.8.5, the fifth major update that Mountain Lion has received since it was released last July.

Upgrade mac 10.7.5 to 10.8