It's been three weeks since I reviewed the MacBook Air, and in the intervening time we've gathered a whole lot more information about Apple's latest, and lightest, laptop. With a month of use under our belts and solid lab testing of three different MacBook Air configurations, it's time for a follow-up look at the MacBook Air.

Clock speeds, hard drives, and speed

Macworld's initial review of the MacBook Air was based on its stock $1,799 configuration, which features a 1.6GHz Intel Core 2 Duo processor and 80GB of storage provided by a 1.8-inch traditional hard drive. In the intervening weeks, we've obtained two 1.8GHz Intel Core 2 Duo MacBook Airs: one with the same 1.8-inch 80GB hard drive, and one with 64GB of flash memory as its primary internal storage device (what Apple calls a solid-state drive, or SSD.)

With those three models, we can begin to extrapolate the effects of the MacBook Air's two main build-to-order configuration options, the $300 processor-speed upgrade and the $999 SSD upgrade.

The results aren't surprising, though they will probably be disappointing to those who had hoped that the extra investment in the SSD option would result in dramatically improved performance. Both upgrades improved performance, with the processor upgrade improving calculation-based tasks such as 3-D rendering and video encoding, and the SSD upgrade improving disk-intensive tasks such as duplicating a file or launching Adobe Photoshop.

In terms of Speedmark, our battery of general-use tests, the base MacBook Air model scored a 124. The Macbook Air with the same hard drive but a 1.8GHz processor improved to a score of 130. The model with both the 1.8GHz processor and the SSD earned a score of 140. To put that in percentage terms, the $299 processor upgrade improved the overall speed of the system by 4.8 percent, while the $999 drive upgrade improved the speed by 7.7 percent.

Of course, speed isn't the only reason to invest in the SSD option. In theory, its lack of moving parts make it a safer storage device, because it's not eligible for the mechanical failures that hard drives with spinning platters can suffer. However, until we get a long-term read on the reliability of the SSD, that advantage remains theoretical.

Life with the SSD

I've spent the past two weeks using a 1.8GHz MacBook Air equipped with the 64GB solid-state drive as my primary system. As difficult as it was for me to remove files from my MacBook in order to fit on the Air's stock 80GB drive, moving to the SSD was almost impossible. My only recourse was to move my 10GB Windows disk image from Parallels Desktop to an external drive. By sacrificing my ability to run Windows wherever and whenever I wanted, I was able to fit within the narrow confines of that 64GB drive.

Generally, I found using the SSD to be perfectly normal. It doesn't seem to behave differently from any other Mac hard drive I've used. Yes, when using the Air with a traditional hard drive, I would occasionally feel a slight vibration and hear a tick-tick-ticking sounds that's completely absent from the SSD model. But it was never loud enough to be a bother.

In terms of speed, launching Photoshop on the SSD version of the MacBook Air is stunningly fast. I've noticed that other applications also seem to launch much faster on the SSD Air. Similarly, the Air with SSD feels more responsive when running numerous programs at once--possibly because the speedy SSD makes the swapping of programs between RAM and disk faster.

If, as we've argued before, the story of the MacBook Air is one of compromises, then my personal opinion is that the SSD option is simply a compromise too far. Is the SSD's minor speed improvement--along with the fringe benefits of no moving parts and completely silent operation--really worth an extra thousand dollars? If money is no object and the amount of data you need on your laptop is extremely limited--in other words, if you're planning on using the Air as a secondary system and spending an extra $999 for an add-on doesn't make you blink--then the SSD option is for you. For anyone else, I think it's an unnecessary luxury, a high-priced item that offers little in the way of tangible value and comes at the cost of valuable storage space.

A battery of tests

My original review of the MacBook Air noted:

My attempts to recharge the Air's battery took a surprisingly long time. Apple says that the behavior I witnessed doesn't really fit with any of its testing; we're working with Apple to get to the bottom of the issue and Macworld Lab will do further battery testing (including both discharge and recharge time) soon to help clarify the issue.

For more Mac news, visit Macworld. Story copyright Mac Publishing, LLC.