Externally, the new MacBook Air hasn't changed at all since launch. Internally, however, it's significantly more powerful. This latest update shows the difference between being thin by starvation and being thin through exercise.

To recap: the latest MacBook Air has the same display as before (one step up from the standard MacBook displays since the Air is somewhat of a "Pro" machine), the same form factor and the same exact feel as the one released in early 2008. On the inside, however, Apple increased both the solid state hard drive and the standard SATA hard drive storage to 128GB and 120GB, respectively. There's also a Mini DisplayPort port connection for the revamped 24-inch Cinema Display, a faster CPU and faster front side bus, plus that Nvidia 9400 graphics chipset that's in the MacBook and MacBook Pros. Here's how the machine stacks up.

Benchmark: The most important thing to measure in this incremental upgrade is the performance comparison vs. other MacBooks. I've updated the chart from the MacBook and MacBook Pro graphics deathmatch (performed with 3DMark 06 under Windows XP) to include the MacBook Air, and it performs about as well as you'd expect in most departments. Since the MacBook Air and the Macbook now have the same GeForce 9400M integrated graphics chip, it makes sense that they're fairly close in score, with the Air falling behind due to the wimpier processor. It is quite a surprise that the CPU test has the Air so far below the MacBook, scoring at only 56% of its cheaper, but fatter, brother. It's still the slowest MacBook you can currently buy.

Battery: In regular blogging use (Wi-Fi on, screen 3/4 brightness, music on, lots of web browsing and webapps), we got a respectable 2.5 hours with the Air. That's about what we got with the MacBook and MacBook Pro when they were playing back movies, something that's more taxing on the system. But on the other hand, when you compare this version to the original MBA when rendering movies, the updated 9400M GeForce graphics actually lowers CPU usage, which helps to extend battery a bit.

Screen: Since it has the same screen as the old MacBook Air, it's going to be just as good—which is to say, better than the MacBook's screen. You get clearer blacks and no color distortion with wider viewing angles off to the side. It's LED-backed and glossy, so those of you who work outside (a light laptop would mean more of you do) may have difficulty finding a good angle to sit at to not get an annoying glare.

Monitor: One very interesting use case with the MacBook Air is to drive the newly released 24-inch Cinema Display. Apple's 24-inch monitor is very much made with the Air in mind, with its USB, Mini DisplayPort and MacBook Air-style slim MagSafe adapter. The good news is that the Air drives this display very well in either mirror mode (lid closed is optional) or as a separate display, proving that the GeForce 9400M is more than enough to run 1920x1200 sans slowdowns. The bad news is that the the laptop's USB and Mini DisplayPort is on the right, but the power is on the left, meaning that the three built-in connectors from the monitor are able to connect, but you get a weird forking thing going on behind the display. Not as elegant as when you plug in the display to a MacBook or a MacBook Pro where all the ports are on one side. But, it's a minor quibble.

General Usage: It's essentially the same laptop but improved, so all of our caveats from our first review apply now. You still need to either use the external USB optical drive or "borrow" one from another machine. It's not a fast laptop when compared to its bigger brothers, but it's not a slug either. People who just want a thin, portable and light machine—mainstream folks—are the primary target. But, at $1799 and $2499 for the 1.6GHz and 1.86GHz versions, the Air still lands somewhere, in both price and features, between the pro user and the casual user, meaning that you should think twice and see if either the MacBook or the Pro would be better suited for you. [Apple]