Apple has released iMac SMC Firmware Update 1.1, which is recommended for recently released iMac models that have been configured with PCIe-based flash storage (see “Apple Updates iMac with Faster CPUs and 802.11ac Wi-Fi,” 24 September 2013). The release improves the Power Nap feature in OS X 10.9 Mavericks so that it runs silently while your iMac is sleeping without spinning the fan. (Free update, 921 KB)
Option-Click AirPort Menu for Network Details
If you hold down the Option key while clicking the AirPort menu in Mac OS X 10.5 Leopard, you'll see not just the names of nearby Wi-Fi networks, but additional details about the selected network. Details include the MAC address of the network, the channel used by the base station, the signal strength (a negative number; the closer to zero it is, the stronger the signal), and the transmit rate in megabits per second showing actual network throughput. If you hover the cursor over the name of a network to which you're not connected, a little yellow pop-up shows the signal strength and type of encryption.