By Prince McLean

Published: 08:00 AM EST

Air Performance: CPU and Graphics

Next to mobility, the Air's second set of engineering tradeoffs involve its processing speed and graphics capabilities compared to its usable battery life, heat generation, and fan noise. The faster things get, the hotter parts become, and the more energy they require. Conversely, a silent, cool, and highly efficient laptop can't deliver barnstorming performance. The Air takes a balanced approach but also makes some risky and aggressive moves.

The Air matches the top performance available at the high end of light, thin laptops, using a 1.6 or 1.8 GHz Core Duo CPU. In terms of performance, small devices such as the EEE PC and OQO are not in the Air's class at all. Even other popular, highly mobile laptops such as Sony's Vaio G and Panasonic's Toughbook R6 achieve their battery life and form factor by using a considerably slower single core processor and limited graphics chips.

Compared to other MacBooks, the Air comes very close to the entry level MacBook in both processor and graphics. It uses the same Intel X3100 embedded graphics chipset as the MacBook, meaning it's not a gamer machine or equipped to drive the native resolution of a 30" display. It does have the capacity to drive an HD video projector, any VGA or DVI monitor up to a resolution of 1920×1200, and provide composite and S-Video output. In comparison, most laptops in the Air's size and weight class only provide basic VGA output.



Memory and Disk

The Air supplies 2GB of RAM standard, which is twice what most other popular ultra mobile laptops include, and in many cases is also more than what those units can be expanded to hold (there's often a 1.5GB ceiling in highly mobile laptops). Models that can accommodate more RAM, such as the ThinkPad X61, are also limited by Windows Vista's inability to directly use more than 3.3GB. Given Apple's previous practice of skimping on RAM and delivering machines that desperately needed an upgrade right out of the box, the Air's liberal provision of RAM neatly works around its lack of future RAM expansion. Users with needs for more than 2GB of RAM will likely not be well suited by an ultra mobile form factor laptop.

The Air provides two hard drive options: the default 80GB 1.8" mechanical hard drive and an expensive option to upgrade to a 64GB Flash RAM solid state drive. Apple has been pushing its iPod line away from hard drives and toward Flash RAM because Flash is faster to read, less fragile and sensitive to impact, and more energy efficient. The downside to Flash is that it is far more expensive. Number-obsessed pundits have actually voiced confusion about why the SSD option is $1000 more for fewer GB.

The obvious answer, of course, is that SSD is still a costly, infant technology. Prices will likely drop rapidly, but the current expense of ultra-high density Flash RAM chips simply makes the SSD a pricy option. For business road warriors, the $1000 cost difference may not be much of a barrier. Standard 2.5" laptop drives used in MacBooks are already significantly more fragile than the full sized 3.5" drives used in desktop computers. However, the even smaller 1.8" hard drive used in the base model Air will have the same increased margin of failure evident in the iPods.

While desktop hard drives are generally expected to live reliably for three years, iPod sized hard drives have a roughly two year expected lifespan, as their AppleCare warranty options suggest. Take a hard drive apart and you'll understand why. Their ultra fragile mechanisms spin platters at thousands of RPM and are read by featherweight arms with a magnetic head that floats over the disk surface on a cushion of air. After just a few minutes of activity, these drives quickly become too hot to comfortably handle. It's amazing they can last as long as they do.

When exposed to regular shock and vibration, the chances of the head touching the surface or otherwise failing quickly rises into the danger zone. Once a disk fails, it is usually impossible to repair and often very expensive to attempt to recover data from. SSD solves all those fragility problems by using electronic chips instead of moving parts. Apple's business in iPods and with the iPhone give it high volume component pricing on the latest SSD devices, but its still an early adopter technology. Apple's SSD offering on the Air should both bring attention to the technology and help push SSD into the mainstream.

The Performance Numbers

The Air's slightly slower CPU, matching graphics chips, slower-spinning HDD option, and fixed 2GB of RAM all make it difficult to compare in absolute ways against the base MacBook. How much difference does the mini hard drive make compared to the CPU? The Air's inability to enter FireWire Target Mode also makes performance testing of its hard drive a little more complicated to neatly isolate.

According to our Xbench testing, the Air compared well against a higher end MacBook and offered very similar Quartz graphics performance. However, Xbench rated the Air's OpenGL so poorly that there must be an error in the existing 1.3 version of the benchmark. That also appears to have skewed the overall user interface score and the score overall. The disk scores reflected the Air's use of a smaller, slower spinning mechanism. The Air's modern chipsets also appear to allow it to outscore our top of the line MacBook Pro from 2006 in RAM testing despite both using a 667 MHz bus, but that may also be an error related to Xbench and the new Air.

Combined, these numbers don't really provide a very useful picture of overall performance. For the uses it was intended, the Air's speed differences in CPU, disk, and RAM combine to deliver a very fast mobile system. Users who browse the web, work with office documents, and use iLife apps should be very happy with its performance. Like the standard MacBook, the Air is not equipped to play leading games such as the new titles released by EA or to run other heavy duty intensive graphics rendering applications.

Despite its focus on mobility, the Air delivers leading performance for its class and respectable performance even when compared against full sized, fully equipped MacBooks. PC World benchmarked the Air running Windows and found that it placed well ahead of light laptops from Sony and Fujitsu, but behind the leading ThinkPad X61, which is considerably thicker but uses the same CPU and graphics chip. PC World didn't outline how much RAM was installed in the ThinkPad, but it would certainly benefit from having a faster 2.5" hard drive compared to the Air's 1.8" drive.

It does seem odd than many observers are blown away that the MacBook Air is not as fast as the latest generation of full sized laptops. When have ultra mobile laptops, even those considerably thicker than the Air, ever matched the performance of full sized laptops?

We haven't yet obtained an SSD model for comparative testing with the base model Air model, but we have witnessed the dramatically faster application launching and rebooting it offers.



Performance Efficiency

The Air is no slouch, but it isn't a hot, loud, battery hog either. I couldn't get it to make any significant heat or noise until I baked the unit until it was unpleasantly hot to the touch. Even then, the fan was rather quiet despite evacuating hot air pretty rapidly from the openings along the back edge.

Apple says the Air's battery lasts for 5 hours with WiFi running. A number of reviewers have reported real world numbers of a little less than four hours. In all fairness, any laptop battery needs to be fully charged and calibrated through a couple charging cycles before reaching its top performance.

To really stress test things, I started playing a ripped DVD via a remote file share using wireless networking. DVD Player played the movie at full screen brightness all the way through once and started back through again for a total of exactly three hours. Playing the DVD over the network was enough work to cause the Air to become slightly warm and run the fan.

A number of factors will make a significant impact on battery life: screen brightness, disk activity, processor use, and WiFi radio activity. Casually browsing the web with the screen brightness dimmed slightly would provide far longer battery life than my pulling an entire DVD through the air. The SSD option, for anyone who can afford it, should also contribute to longer battery life. Three to four hours of use is better than other MacBooks, but given that there's no way to swap around battery packs, the Air demands to be used within a few hours proximity to power. With the increase in laptop use, finding an outlet in class, at work, in public spaces, and on airplanes is becoming easier, but some users will cling to models that allow them to carry spare batteries.

On page 3 of 5: Design Factors: the Missing Features; Built-in Optical Drive versus network Remote Disc or optional SuperDrive; and WWAN radio or expansion bay versus option to use a USB Dongle.