The right side of the 13-inch Air continues to host an SD card reader. On both sizes, the left side sports a tiny microphone along with a 1/8-inch (3.5mm) headphone jack that also supports headphones with an Apple-style inline remote/microphone module.

Still missing, of course--but missed less and less every day--is an optical drive. And the Air still omits an ethernet port, although those who need that capability--for faster networking or for security requirements--will appreciate the new $29 . Unfortunately, unless you've got an Apple ( Macworld rated 4 out of 5 mice ), you can't use the adapter and an external display at the same time. (We're testing the performance of the Thunderbolt Ethernet adapter and will update this review with the results.)

The Air continues to support 802.11a/b/g/n wireless networking and Bluetooth 4.0.

Some of the new Air models' biggest changes are found on the inside. For starters, the 2012 Airs use Intel's third-generation Core processors (also known as ) for better performance, making Apple one of the first vendors to adopt these chips in their non-workhorse lines. Specifically, the 11-inch Air uses a 1.7GHz dual-core Core i5 processor with 3MB of shared level--3 cache, while the 13-inch Air uses a 1.8GHz version; a 2.0GHz i7 processor with 4MB level--3 cache is available as a built-to-order option. Like the previous Core i5 and i7 processors (known as ), Ivy Bridge CPUs include hyper-threading and Turbo Boost. Hyper-threading lets the CPU's two cores be utilized by the OS as four. When only one core is needed for a task, Turbo Boost lets the chip shut down one of the two cores and bump up the clock speed of the other. Turbo Boost can reach 2.6GHz on the 1.7GHz i5 and 2.8GHz on the 1.8GHz i5. Turbo Boost on the 2.0GHz i7 CPU can reach 3.2GHz.