And a small drive doesn't just limit your storage--it can also affect performance as the drive fills up. As Macworld lab director James Galbraith , we couldn't fit all of our standard test files on the 64GB system, and even after removing some of our test files in order to be able to run other tests, the $999 Air was only 7 percent faster than last year's model at file-intensive tasks. If you can afford the upgrade (see below), go with the 128MB of flash storage.

That aside, all these improvements add up to a nice overall speed bump. For example, when we tallied our overall performance benchmark, , a 128GB 11-inch 2012 Air was 28 percent faster overall than the equivalent model last year, and a 128GB 13-inch 2012 Air was just under 20 percent faster than the equivalent 2011 version.

How do these improvements translate to real-world use? I timed how long it took to perform a number of everyday tasks on the 2012 11-inch MacBook Air (4GB RAM) and a 2010 11-inch Air (2GB RAM), each with 128GB of flash storage. (I performed each task several times and averaged the results.) On the 2010 Air, iMovie loaded to a new project in 5.5 seconds, iPhoto launched into an empty library in 2.8 seconds, and Safari launched and loaded Apple's home page in 2.7 seconds. On the 2012 model, iMovie took just under 3 seconds, iPhoto was ready in 1.2 seconds, and Safari finished launching and loading the Apple home page in 1.8 seconds. The 2012 Air also cold-booted into the Finder, with auto-login enabled, in just over 15 seconds; the 2010 Air took over 30 seconds. And our lab found that the 2012 model was a whopping 67 percent faster than the 2010 model in our HandBrake test, which involves converting a DVD chapter to an MP4 file.

If you're curious, we also compared the new Airs to a 2012 , 8GB of RAM, and a 5400 rpm hard drive. The MacBook Pro scored roughly 26 percent higher in our Mathematica test, and was roughly 28 percent faster in our Cinebench CPU test. But because it uses the same Intel HD Graphics 4000 GPU as the Air line, the MacBook Pro was only a few percentage points faster than the 2012 13-inch Airs at the Cinebench test and 12 percent faster in our Portal test. But perhaps most suprisingly, thanks to the flash storage, of the 2012 128GB Airs (11-inch and 13-inch) bested--by 3 and 6 percent, respectively--the i7-equipped MacBook Pro in our overall Speedmark benchmarks.