Troubleshoot your misbehaving Mac with Apple’s Hardware Test
On those rare occasions when a Mac starts acting a bit uppity, most of us turn to Apple’s Disk Utility as our first attempt at setting things straight. If Disk Utility cannot repair the problem, our next step is usually a 3rd party disk repair utility such as Alsoft’s Disk Warrior. However, there are times when the problem doesn’t stem from faulty software or hard disk corruption. Sometimes the problem can lie in the hardware itself.
If you are experiencing frequent kernel panics or random shut downs, perhaps it is time to take a look at the little-known (and free) Apple Hardware Test app that ships with every Mac.
As most people know, rebooting your Mac from the software restore CD that comes with your Mac by holding the “C” key during will allow you to run Apple’s Disk Utility app. However, if you restart your computer with that same disk in your DVD drive and hold down the “D” key, you will be treated to a bit of nostalgia in the form of Apple’s Hardware Test. (Note: AHT will not run from a standalone OS X DVD, only the software restore DVDs that ship with each Mac).
Apple Hardware Test may seem like Disk Utility’s ugly step-sister, but it serves an entirely different purpose. Looking very OS 9-ish, the Apple Hardware test allows you to run a series of tests on your system’s RAM, logic board, modem (if present) video RAM, and Apple’s Airport Card. It will not test 3rd party video cards, PCI cards, or Non-Apple devices, but you should have tried trouble-shooting those devices already by this point.
There are very few options to choose when running AHT, in fact there is only one. You can either choose to run the basic test, or check the “Perform extended testing” check box. Apple warns using this option will take considerably longer, and depending on how much memory you have, it does make a difference. The basic test on our Mac Pro with 4 GB of RAM took about 4 minutes, the extended test took about 20.
Apple Hardware Test also consists of a version of the Apple System Profiler, and allows you view your computer’s memory configuration, video card info, active communication ports, and basic system info such as your serial number, Boot ROM version, and model number.
All in all we think AHT is a very simple and well designed diagnostic tool that more people should be aware of, and one that all people should add to their trouble shooting arsenal.