NewsMemtest86+ Adds Intel Mac Support (Second Update)
Memtest86+ was updated to version 2.01 today. The ultimate memory tester added several new features to its battery of memory tests… but one in particular stands out: Mac support.
The application is one of the most recognized software diagnostic tools on the planet. Based on its less-updated competitor, Memtest86 (no plus), the application runs test after test in a looping pattern. It’s simple, and exhaustive. After about three passes of the test, you can be fairly confident that the RAM won’t fail under the worst of circumstances. It’s so good, Microsoft photocopied its tests and appearance in their own Windows Memory Diagnostic (which is a completely different app, written in WinPE, but it serves the same purpose and looks nearly identical to Memtest86+).
While there has been no technical limitations barring Memtest86+ from running on Intel-based Macs (it is powered by a minimalist Linux kernel), the program has needed Linux tweaks key to adding support for Intel-based Macs to boot the Linux operating system. This update added those changes, and now Intel-based Macs can be supported.
One problem does arise however… Memtest86+ is much more meticulous at testing RAM than even Apple’s own internal hardware test diagnostics. It will be possible that bad memory in a Mac will pass Apple’s battery of tests, but fail Memtest86+. I can only think of the arguments that will ensue between the Genius Bar and the customer when that happens… it will make Parking Wars seem almost trivial.
As I was writing this article… I decided to give it a try. Guess what? Memtest-86+ found memory errors within a minute. Apple’s own internal service diagnostic? A clean bill of health. Same with Apple’s hardware test disc included with every Mac. It’s third-party RAM, but it’s good to know that it’s bad… I now have to mail it off for replacement to OCZ, who made/sold the RAM.
Update: I’m not sure that Memtest86+ is ready for Mac just yet. It may be giving false positives… let me know what your results are. I’ll be getting in touch with the developer…
Update 2: Memtest86+’s developer has confirmed to me that there are issues with Intel-based Macs. He is investigating the cause… but there is no timeframe for when it will be fixed.
(Hopefully) false positives here, too; figured I’d give it a try on my recently upgraded macbook (brand new 2×2GB Mushkin), reported a slew of errors. Was about to initiate RMA, and then decided to swap in the stock ram, same issue (not the same addresses, but a ton of errors). And I’d not had any problems with the system.
Was your keyboard working? Mine wasn’t, not sure they’re supporting USB keyboards?
You ever get a hold of the devs? I didn’t see any similar reports in the forums since September, when the original patcher for mac support apparently mentioned he was seeing similar issues… Though there’s a french section in the forums and I don’t speak french…
Anyways, good luck to you; perhaps I’ll post something to the forums. There’s support for a serial port but I’m not sure that really maps to any of the macbook’s hardware…
Nobody else tried this yet?!
Thanks for reminding me, I’ve posted an update above.
The only system you’d be able to use the Serial port on, is Intel-based XServes, which do have an RS-232 port on them for access and control. I wonder if that is routed so it would work without a drive (it could be powered by USB, not sure on that).
I ran MemTest on a Macbook Pro with 4GB (2×2GB) and once per stick. Each test produced about ~1500 errors. Apple Hardware Test said that the RAM is “fine.”
Can confirm this on a MacBook Pro 17″ with new Crucial 2×2GB RAM. Spews errors.