Hot laptops: how to cool them down

[Friday, May 16th]

We previously reported on MacBook Airs that appear to be overheating under various circumstances for some users, resulting in freezes. Overheating laptops collectively represent a recurring theme across Apple's line. We've gathered some tips for cooling the systems down.

For some users, laptops seem to get exceptionally hot with general use, or when put to sleep. This happens randomly, though with ever increasing frequency, and can lead to crashes or other faulty system behavior. It is exceptionally important to deal with overheating, and not allow your computer to get to the point where it is uncomfortable to pick it up or hurts to the touch. First, be sure when operating the computer that it is on an open surface and not crowded or packed in an insulating environment (such as on a bed or against clothes) for too long, and that the vents are not blocked.

Unusable System Management Controller settings Heat generation could be caused by hardware management controllers not managing power properly. According to Apple's Knowledge Base article regarding the system management controller, settings may become unusable with computer use:

"Over time, the settings in the System Management Controller may become unusable, which can result in operational anomalies with the computer. Examples include not turning on, not waking from sleep, not charging the battery, or not recognizing the AC Adapter, among others."

This pertains to both the faulty sleep behavior and battery issues. If persistent heating problems occur, resetting the SMC according to Apple's instructions may help.

Faulty sleep functions The sleep functions on laptops can be rather touchy (laptops not waking, etc). For some folks, after putting their computers to sleep the systems have gone into a power-consuming mode where they generate a lot of heat. This leads to faulty hardware function (screen splotches, crashes, freezes). One user notes after his MacBook Pro had trouble displaying on an external monitor after sleeping, until he powered it down:

Be sure that any scheduling software is turned off, be it either third-party applications or the built-in energy saver settings. Additionally, resetting the SMC as mentioned above should help if problems persist.

Faulty battery A faulty battery (or temporary mismanagement of battery resources) could also cause excessive heat. If a battery is signaling that it is not holding a charge, or that it is empty, then the system will constantly try to charge it up, resulting in massive heat generation. Alternatively, a faulty battery can also drain fast when not plugged in, causing heat generation as well.

Apple suggests calibrating the MacBook/Pro battery on a Monthly or Bi-Monthly basis to keep it fully functioning.

While these problems could be temporary and fixed with a simple restart or shutdown, if they persist or become more frequent then resetting the system management controller can also help.

Feedback? Late-breakers@macfixit.com.

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