Apple tries to cool 'hot' Airs

Although Apple updated its MacBook Air this week with a fix for the laptop's fan, some owners of the ultra-thin notebook continue to report that their machines overheat and stagger to a stop when watching video or playing games.

On Monday, Apple issued a MacBook Air patch dubbed "SMC Update 1.0" that the company tersely said "fine tunes the speed and operation of the internal fan." In Apple's terminology, SMC stands for System Management Controller, which is a chip on the laptop's motherboard responsible for power management.

The SMC update followed complaints by MacBook Air users that began shortly after the waif-like notebook reached buyers in early February. Those reports claimed that the Air would overheat, then either shut down entirely or shut one of the two processor cores on its Intel Core 2 Duo processor.

"My MBA would freeze up and then unfreeze and then freeze again, at an interval of about 10 to 15 seconds," wrote a user named RichardY late last month in a message posted to the Apple support forum. "This happens when I watch video on iTunes, QuickTime or even those Flash based videos such as YouTube. CPU monitor shows one core shutting down itself when this happens, and the other core would run at 100 per cent (roughly half for user and half for system)."

"After watch[ing] around 4 minutes of any YouTube content, the behavior starts to show up," added Deny Dias on the same thread in a March 7 message. "The 'magic' number seems to be around the 163o F (73o C). When MBA goes beyond this temperature, the CPU bar graph of Activity Monitor show a slow down on core #2 while the core #1 raises up to the top." Other users noted that the fan inside their MacBook Air would crank up to flank speed, and make more noise than they wanted to hear.

The whole experience was exasperating to many users, although some took it in stride. "Actually, this sheds some light on the limits of this notebook. From the looks of it, its performance range is limited and fixed," said "mac wison" on a separate thread in the same forum. "Which is understandable, as it's an unusual design."

After applying the SMC update, however, some MacBook Air owners said they were disappointed. "Makes absolutely no difference," said Pagemaker2. "My fan is exhibiting no better performance/quietness after the update. Absolutely nothing that I can see or appreciate."

The MacBook Air's teething problems aren't unique in Apple hardware history. Early versions of some of Apple's MacBook Pros, for instance, had a habit of sounding a high-pitched squeal, while first-generation iPod nanos came with scratch-prone screens.

The SMC update can be downloaded from Apple's Web site, or can be retrieved using the MacBook Air's built-in Software Update command.