Bad RAM in Mac Pro

Posted by: Biggerfoot

Bad RAM in Mac Pro - 10/15/09 04:17 PM

This is a first for me. I went to wake up my Mac Pro (3.2 GHzQuad-Core Intel Xeon 2008) and it would not wake. After reseting everything, still no chime, just a flashing power light and the video card fan would come on.

I have 16 gigs of RAM...2 gig chips from OWC.

It took awhile to get to the RAM but sure enough, after pulling the RAM chips by pairs, I found one that kept it from booting. I stuck in the Apple pair of RAM and left the other 14 gigs in there.

It seems to boot fine now.

I never had RAM this common?

Posted by: MacBozo

Re: Bad RAM in Mac Pro - 10/15/09 04:23 PM

About as common as HD failures.
Posted by: Reboot

Re: Bad RAM in Mac Pro - 10/15/09 05:23 PM

Yep, it happens. I ran across a G5 tower a couple of weeks ago that had ran for a couple of years fine then wouldn't boot up one day.
Posted by: NucleusG4

Re: Bad RAM in Mac Pro - 10/15/09 11:36 PM

It has happened to me twice...luckily ram has a lifetime warranty these days...
Posted by: Biggerfoot

Re: Bad RAM in Mac Pro - 12/14/09 06:22 PM

Wow, I just now had my third of eight OWC RAM chips in my 2008 Mac Pro fail.

After reading around, it seems others have had similar luck with their OWC 2GB RAM failing in their 2008 Mac Pros.

OWC does replace the failed chips but of course, I have to pay for shipping back. I am assuming the rest will fail sooner or later at this rate. The computer is in my home so it is not under lots of stress or in a bad environment. The person I talked to at OWC would not say if this is a wide spread problems with these chips. They were the first to release aftermarket RAM for this Mac Pro so maybe they were not ready for primetime when they shipped them.
Posted by: Reboot

Re: Bad RAM in Mac Pro - 12/14/09 06:49 PM

If you want to put the hammer to it and really heat them up try memtest. Let me see if I can find the post about it I did here.

Here it is revised.


memtest Not free but $1.39. I've had it find find bad RAM when Apple's hardware test couldn't. Run it in Single User mode first, that way it only uses about 50M to boot up and will test the majority of the RAM. Processor caches are disabled in SU mode, so If you double click memtest while running from a regular boot it will also test the processor caches, but less RAM, since it takes more RAM to boot regular.

A way to get it free is to download Rember, then go to Show Package Contents for Rember, Contents/Resources/ and copy the memtest file out of there onto the HD. Here's the user's guide. You don't get it with Rember, only with the memtest d/l version, guess it's worth the $1.39 for the guy that wrote it. Memtest is open source.

Copy memtest to the top level of your HD, and to run it boot to Single User mode, then type /memtest*all*6*-L. * = space. /memtest invokes the app, all tells it to test all available RAM, 6 tells it 6 passes, -L puts a log on the top level of the HD.

It takes about an hour or so on my dual 867 to run one pass of 2G of RAM. You want to run a few passes to really heat up the RAM to i ncrease chances of showing marginal RAM. I've had it not find bad modules on the first pass or two. Any error is not good. If the machine locks up it's not good. If it does remove one module and retest. It doesn't have the ability to tell which module is bad.