Memtest - 4.22

It's one thing to charge for the software, but as I understand it, this is open source software that he's modified, so any changes he makes to it are required to me made open source as well. By putting it behind a locked door (i.e. you don't get the source until you pay for it) he's breaking the license, last I checked.

Whilst this is a really useful troubleshooting tool, the developer has decided to charge for each download - so technically this is not shareware, but a commercial product, but with no update provision. The developer indicated to me in an email that it was 'all too hard to do it any other way' when I queried this. Strange, but true.

So, even if you have paid the 1.39 charge to download a previous version, if you wish to download the latest version you must pay again, regardless of whether it is a major or minor update. When you 'purchase' the software you are given an expiring URL to your download. If you need to redownload there is that option to request a new URL, but this is just for the version previously downloaded, not the latest version. You get a password protected .dmg which you unlock with a password provided with the URL email.

Whilst I'm not sure that you can produce a demo of a CLI software, I would have thought the password-protected .dmg would be sufficient to allow paying supporters of the product to stay current with bug fixes etc, rather than have to pay each and every time - otherwise what incentive is there to support the developer? This needs to be made clear.

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.

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.

After using the installer for Memtest, the files were scattered throughout my root directory. A simple drag and drop installation might be better.