Memtest for Mac

User Reviews

• Tests all memory in Tiger

  ellaj--2008August 16, 2006

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  This review was originally posted on VersionTracker.com.<br />I just want to point out that memtest does indeed test all available memory if running on a 64-bit machine under Tiger. I also agree with the other reviewers that memtest finds errors that Apple Hardware Test misses. I have 5.5GByte installed on my G5 2*2GHz, and memtest found several errors, although AHT found nothing. To identify the culprit was not an easy task, however, since the results obtained removing and putting back memory modules were not quite repeatable, even when running in single-user mode. Checking this much memory is also quite time-consuming, and the fan runs at top speed all the time... I finally solved my problem by changing the order of the DIMMs, putting the largest memories in the first pair of banks, and smaller memories in the later banks. As far as I know, the order shouldn't matter as long as the pairs are of equal size (and preferrably brand), so maybe it was just the fact that all modules were plugged out and then back in that did it, but now I can run memtest without errors with all memory installed. Hope this can help someone.

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• identified bad DIMMs that Apple Hardware Test &...

  doubleechoDecember 5, 2005

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  ...Tech Tool Pro missed<br />This review was originally posted on VersionTracker.com.<br />i was having intermittent problems with my dual 2.5GHz G5. i wiped the hard drive, clean install of OS 10.3.9, and essentially no unusual 3rd party software. Apple Hardware Test and Tech Tool Pro both said everything was fine. Memtest proved them wrong! though i had to swap DIMMs around several times to identify the bad ones, i was able to find one DIMM that was really screwed up and another that only had one or two errors (still worth replacing). i've removed them both, and all is now well. without memtest, i'd have spent countless hours pursuing a non-existent software conflict as the root cause instead of what i know now to clearly be a previously undiagnosed hardware problem. the author, tony scaminaci, was exceptionally responsive to a couple of simple questions from me. i particularly appreciated that as i ventured forward into new territory. kudos to tony. unclear to me why apple hardware test and tech tool pro haven't incorporated the algorithms from memtest into their products since memtest found problems that AHT and TTP both missed. the documentation recommends single user mode (unix command line prompt) for the most reliable and thorough test. i'm a big chicken when it comes to command line prompts (that's why i have a mac, of course!). but, this version runs fine from the desktop. memtest can only reserve about 2GB of memory at a time, but from the desktop several occurrences of memtest can be run at the same time. i found 2 bad DIMMs before i ever needed to simultaneously check all 8 DIMMs in my computer, but i did have 3 memtests running at the same time checking 6 DIMMs. i also recommend using Rember, a close partner to memtest. it provides an easy way to quit all programs without having to quit them individually. memtest is not without its deficiencies. as i mentioned, it will only test the first 2GB it can lock, and you don't get to pick which 2GB that is. so, if you have more than 2GB, you have to run more than one memtest at a time. would also be nice to be able to test the first 512MB or so of memory that the desktop uses before memtest even starts. the only way i could check that memory was to swap those DIMMs with known good DIMMs from earlier tests. when memtest identifies a fault with a memory location, it doesn't correlate the error to a specific DIMM. so, i had to swap DIMMs in and out many times in a logic pattern and correlate the presence or absence of errors to the changes in DIMM configuration. the documentation was sufficient, but perhaps a bit sparse for a novice like me. though i got the job done, i had many questions as i went along. most of the time i could infer the correct answer, but a couple of times i had to experiment a bit to figure it out. don't read too much into my nitpicks. remember that memtest is free, but it solved problems that both AHT and TTP missed. that makes memtest invaluable, worthy of a five star rating for this stage of its development, and an important tool in every macintosh owner's box of tricks.

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• Saved me...

  RSoldinMay 29, 2005

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  This review was originally posted on VersionTracker.com.<br />I was having some very strange problems on my QuickSilver dual 1 gig with 1.5 gig of ram. I troubleshot the problem for weeks getting very frustrated not finding a sure. One day I realized I hadnâ??t check to see if my ram was bad. I downloaded this little helper and it found one of my DRAMs was bad. I pulled the ram and all the problems went away. Thank you, Rick

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• Single-User Mode

  amcgeeMay 29, 2005

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  This review was originally posted on VersionTracker.com.<br />1. Let's get the self-evident out of the way: it is absolutely pointless and a waste of time to attempt to test RAM while booted into OS X in GUI mode. At the very least, you might get some minor benefit if you did the testing in safe mode, when the least amount of memory is being taken up, but even that is ridiculous. There simply is no alternative when properly testing RAM than to do it in single-user mode, or when booted from the Apple diagnostics disk. Forget about Rember and anything else that supposedly holds your hand, programs such as those are actually doing you a disservice by giving the illusion that something useful is happening. The reality is that they are crippling you and helping to hide problems that could be detected if the testing had been done right in the first place. Take the time to learn how memtest works in single-user mode. You have no other viable choice. 2. When running memtest in single-user mode, you may have to experiment a little in order to get it to work. Even though the program tries to auto-detect the maximum amount of testable RAM when using the "all" parameter, on some systems it grabs too much, and this causes the program to hang. I have 1500MB on one machine and memtest autodetects about 1430MB of testable RAM. Unfortunately, that's still too much, and I usually have to specify 1400MB as the max amount, after which memtest runs perfectly. So, don't be discouraged if it hangs, just substitute a specific amount of RAM below the autodetected amount, instead of using "all." 3. Depending on how much RAM you have, memtest can take a long time to finish. It's much more thorough than the Apple diagnostics, so don't be surprised if you start it and it's still running an hour or more later. Memtest is not something you run on your lunch or coffee break, but rather, you start it and let it run overnight, or when you don't need the machine for awhile, especially if you specify more than one test iteration. 4. The proper place to put a command-line utility like memtest is NOT in your /Applications folder, nor should it be placed in it's own directory at the top level of your drive, but rather, the best place to put these types of third party shell apps is in the /usr/local/bin directory. Now, if you're a sysadmin, you already know what to do next, but if you're not a sysadmin, and all this is a bit scary, then the next alternative is to place it in the ~/Applications directory of your admin account. This will insure it's accessible to you when booted into single-user mode, but avoids the other commands you'd need to issue in order to make sure it's stored correctly in /usr/local/bin. Ideally, all this complexity and decision-making could be avoided if the developer were to write an installer that worked like the one for AppleJack and/or if memtest were to make it's way into Fink or DarwinPorts.

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• Great tool!

  robotspacerDecember 9, 2004

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  This review was originally posted on VersionTracker.com.<br />Ran it in single user mode to test all of my RAM and it worked great. Very easy to use so long as you follow the instructions, though some familiarity with the command line helps. My only suggestions, to make this easier for the less technically-inclined: - Package it better, either as an installer or a single package (.app), rather than just a confusing folder of files. - The documentation could be clearer. I'd include as-simple-as-possible step-by-step instructions first (including how to start in single user mode), with a separate section on advanced options. Put the release notes after the instructions.

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• Not responding

  VersionTrackerUserOpinionAugust 29, 2004

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  This review was originally posted on VersionTracker.com.<br />I downloaded Memtest today. I tried it on single-user mode, using as command line (which wasn't clear in Readmefirst): Applications etc; ./memtest all 1; memtest; memtest all 1. Each time I was told in one way or another, no comprendo. So I ran my Appejack which told me my Terminal stuff and Desktop stuff was all a-okay. I tried all my conceivable options again on single-user mode. Same. Then I went to the Desktop and tried the Bash program, all the options again that I could think of for the command line. I constantly referred to the Readmefirst. I had placed my downloaded Memtest app in the Applications file as instructed. Applejack always works fine, I use it once a day before I shut down my Mac, and I go to sleep myself. I run a few command lines from sources, very basic, just so I slowly buildup familiarity with the Unix stuff in my iMac (Panther 3.4). Sorry, but I'll give one star until I have reason in my own experience to do otherwise. Owlb (aka owlhoot_dotmac)

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• Awesome RAM Testing Utility!

  mshepherdMarch 9, 2004

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  This review was originally posted on VersionTracker.com.<br />This has helped trememdously. Has extensive memory testing capabilities. Easy to run at the command line. Just works!

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