Troubleshoot your misbehaving Mac with Apple’s Hardware Test - Macenstein

Troubleshoot your misbehaving Mac with Apple’s Hardware Test

Posted by Lab Rat

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.

22 Responses to “Troubleshoot your misbehaving Mac with Apple’s Hardware Test”
  1. init says:

    wow, that DOES look old-school. Takes me back. It’s funny to think there are Mac users out there now who never even saw OS 9!

  2. Funzo says:

    Never knew about that, thanks!

  3. Anonymous says:

    you know you can loop it too

  4. Anonymous says:

    control – L

  5. ed says:

    Pretty dam cool.

  6. Sam says:

    Also check the following video for more mac os x tools that could help you monitor the performance of your mac:

  7. Tong says:

    Actually AHT doesn’t even test the disk so it’s not very fair to compare it to Disk Utility. It’s also not very useful as maintenance software since if it reports a problem, generally the only way to remedy that problem is to replace a component.

  8. huh? says:

    Tong, when do they say to use AHT instead of diskutility? They are merely saying it can help pinpoint hardware issues diskutility can’t. Use both if you have a problem. There is room for all.

  9. odog says:

    how do you start the hardware test?

  10. charles says:

    What’s crazy is I’ve been instructed to run this before by AppleCare. It has no fan controllers (at least not on the iMac G5), so the cooling fans crank up to full blast!

  11. tech says:

    thanks for it , Lab Rat

  12. Harley says:

    “It’s funny to think there are Mac users out there now who never even saw OS 9!”

    It is good there are users who never saw OS 9.

    I’m glad that by the time my kids are grown up, they will never have had the same trouble users had with earlier operating systems (OS 9 and less, Win ME and less).

  13. John says:

    Thanks… it’s hard to find information on this utility out on the web. One difference for iMac G5s is that you hold down “option” instead of “d” at boot.
    Thanks too to Charles… I was wondering why the fans went crazy!

  14. Cathy Kratovil says:

    Sure hope you guys are still following this discussion. I’ve downloaded the Apple Hardware test for iBook, have a tangerine clamshell iBook running OSX.3 and having problems with the Airport card, computer not recognizing, telling me it’s not installed. I would like to run the hardware test to check the Airport drive, if that’s possible prior to sending back the card, taking the chance that the card is O.K. and being charged a fee for this. Any suggestions are helpful. Just really want to use this for a wireless connection because I was down for an entire week, thanks to Verizon’s inability to service it’s customers in timely manner. I’m a graphic designer and depend on my Internet connections. Thought this would be a quick fix, as opposed to running to the local library, waiting to use their system, dealing with screaming kids (by the way — what happened to the idea that the library is supposed to be a quiet place???), only having 45 minutes to do 8 hours of work, etc. blah so-on ….


  15. Ben says:

    I just ran the hardware test, and when it got to testing the video ram, a strange multi-colored pattern overtook the screen. It scared me and I aborted the test. Is this normal?

  16. Mac says:

    @ Ben: yes, is normal, it’s the video test, just wait and it will turn back to normal….

  17. Tom Eubanks says:

    Have got all sorts of strange pixilated patterns on screen.

    Ran hardware test an video ram gave error code disp/13/2.

    How bad is my problem?.

  18. John says:

    Hi can someone tell me when doing an extended test (or basic test) can you just click start and walk away from the computer and come back when the test is over or will the test ask you for prompts so you have to be infront of it while it does the test ? regards john

  19. Serge says:

    @ John: You can safely walk away from the extended test while it’s in progress, it won’t prompt for anything during the test. But it usually doesn’t take that long, 20 minutes would be long, referring to the 20 minutes it took for the Mac Pro with 4 gb of memory. Usually takes more like 5-10 minutes on average.

  20. Eddy Stein says:

    This test has been testing the RAM for 37 minutes now, and counting. This machine only has 1 GB of DDR RAM. I may have to abort the test manually (no error message so far).

  21. Jason says:

    With the hardware test being located on the Mac install Disc, do I need to make a full backup of the contents of my computer prior to running the test? Thanks in advance…

  22. Will says:

    Been running the extended test on a Mac mini with 4gb of RAM for about 30mins now.
    I wish this comp had the luxury of those 10min extended times yall are talking about. XD

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