HELP! New (2009) 8-core not recognizing memory

Discussion in 'Mac Pro' started by Wheetman, Apr 28, 2009.

  1. Wheetman macrumors member

    Aug 9, 2007
    So, it has finally arrived. My first ever Mac. an 8 core 2.66ghz Mac Pro with 6Gig of Ram from Apple. And after years in the darkness, Boy! I am impressed. That is until I decided to get brave and install the 6x4 Gig Memory Modules I had shipped to the UK from OWC. Following all precautionary advice, I removed the Apple Ram and installed the 6 Modules in 1,2,3, & 5,6,7 just like the manual says. Put everything back together and re-booted.........Nothing! Only a flashing status light. Incidentally, no pauses between the flashes, just repeated 1 sec interval continuous blinking.........The next 5 hours I'll not bore you with, but it involved moving the memory around and trying different configurations. The most I could get recognized was 4Gig out of the 8 I had installed at that particular time. I e-mailed OWC, but am still awaiting a reply. Put the Mac Memory back in and no problem 6x1Gig instantly recognized.

    Today, I had another go and managed to get 16 Gig recognized at one point. I then added the other two modules (Without touching any that were already installed) and got a red LED on bay 2 & 6, which had worked ok on the previous attempt. Tried moving a few of the modules around and get the same lights lighting up. I think one module at least may be kaput, as that brings up a red LED wherever I put it. Totally frustrated by this time, I put the original 6Gig of Apple Memory in and no problems. Please, Please, Please has anyone encountered this problem before and is there a cure? Being a Newbie, is there something I should have set before upgrading to the larger RAM?...I didn't see any requirement to do this in anything I read. The modules can't all be bad, given that they have shown to be working before. What I do not understand is why a module should trigger a red LED when at the last reboot it was working ok. Any advice would be very much appreciated.:confused:
  2. stonyc macrumors 65816


    Feb 15, 2005
    Hmm, speaking from experience in the PC world... the best way to find out if a particular stick of ram is bad, or if a specific ram slot is bad is to:

    1) label each of your sticks of ram, maybe a piece of tape with the number 1-6 on each.

    2) proceed to test 1 stick at a time in each slot and see if the machine will boot or if you get the LED error

    You'll know if you have a bad ram slot if none of the sticks work in that slot. From your description, the original Apple ram works therefore I would suspect the ram before the slots. But still, it's best to test each slot separately just in case. Just as an FYI, a definitive test for bad ram will require you to do each stick separately... putting in a few sticks at a time may help you narrow down, but it won't tell you anything definitively.

    Once you figure out which stick (or sticks) is the culprit, you should be able to contact OWC and RMA (return merchandise authorization) the offending stick. They should replace it for free, but you may have to pay for shipping (I know a lot of places like Newegg will send you a shipping label for free).

    Hope that helps.

    Oh, yes... it will be long and tedious. But you'll be much happier finding the actual fault (especially if it is a stick of ram and not the ram slots).
  3. Corax macrumors 6502


    Apr 27, 2009
    Willemstad - Curaçao
    Did you also perform a PRAM reset after you installed the memory?
    Please read all documentation about installing memory in your 2009 Mac Pro before acting.

    For a PRAM-reset do the following:
    When turning on the Mac, during the startup sound (chime) keep the following four keys pressed: Alt-Command-P-R release the keys after hearing the startup sound a second time.

    Ohw yeah, were you also connected with a metal wire to the ground? When not, static electricity is a memory killer. Always ground yourself when handeling memory.
  4. Wheetman thread starter macrumors member

    Aug 9, 2007
    Just returned from my evening meal. Thank you for the suggestions so far. No I haven't done a PRAM reset, but I shall go and try that now and report back later. And yes, I do work with an anti-static wristband on whenever handling the innards.
  5. rmpstudio macrumors member

    Mar 15, 2009
    I'm not trying to be a smart-ars but what does resetting PRAM have to do with his problem? What's stored in PRAM When to reset PRAM

    If it worked then just ignore me :)
  6. xparaparafreakx macrumors 65816

    Jul 29, 2005
    From OWC
  7. Wheetman thread starter macrumors member

    Aug 9, 2007
    Thank you. As stated in my original post, I did remove all Apple RAM prior to adding the new modules.
  8. mchalebk macrumors 6502a

    Feb 4, 2008
  9. Wheetman thread starter macrumors member

    Aug 9, 2007
    After a day and a half of struggling with this (and yes, it is tedious) I managed to isolate two modules that were defective. One will not work in any of the slots - bringing up a red LED each time I tried it. The other, although functioning (just) brought up a red LED on 6 out of the eight slots and when working was recording 842 EEC errors! In my book that warrants a trip back across the pond for a warranty replacement. At the time of writing I am running with the surviving 16Gig all working. As for the PRAM reset, Its covered in the manual for when the Mac will not boot. Interestingly, it is indexed under RAM. Having faffed with placing and replacing the modules repeatedly and having no red LED illuminated a reboot brought up the optimization suggestion that the modules should be repositioned. They were in the right slots, but one wasn't being recognized - showing as empty. Another reboot attributed the 'empty slot' to a different module and recognized the previously declared missing one. A further reboot repeated the error message on a third module. It was only after resetting the PRAM that all four modules were correctly recognized and the full 16Gig showing. So there is the purpose, I guess, behind restting the PRAM. Like you, I can't see why this should be, but it worked for me, so I am grateful for the suggestion. It will be interesting to see what happens when I get the replacement RAM delivered and installed. If there any changes, I shall upfdate this post later.
  10. Wheetman thread starter macrumors member

    Aug 9, 2007
    Hot off the press is this reply Sunday's plea for help from OWC.. I am pasting it in its entirety as it may help others with a similar problem:

    Here are some things to try when you have suspected memory issues:

    1) The first step is to make sure the memory is installed and seated all of the way. This is the most common solution to having a problem with the memory. If you are unsure of how to install the memory properly you can see our install videos .

    You can also get installation pdf instructions from Apple's site at their Do-It-Yourself center:

    With new memory a common problem is that people do not realize the chips take as much pressure to push in as they can and fail to put them in all the way. Even if your old chips do not take as much force to insert new chips can take a fair amount more force on them to get them to snap fully in to place properly.

    2) Zap your pram. If you need the steps you can refer to the Apple article .

    3) a. For PowerPC machines follow that up with resetting the nvram if you need to. The information on that reset is on the same article as the pram reset from step 2.

    b. For Intel systems the next thing is to try resetting your SMC. For Mac Pro's visit the Apple article . if using a Macbook/MacBook Pro Apple has the article on how to do so .

    c. For Intel based iMacs or Minis to reset the SMC visit the Apple article at .

    4) Try moving your memory to different slots to see if the slots may be a factor.

    a. If mixing memory try the new memory without the original memory.

    b. If you bought multiple chips then try with only one chip at a time and see if the problems show up or not. Repeat per chip or pair purchased.

    c. If you bought multiple pairs, for G5s or Mac Pros, try mixing the chip pairings to see if you can narrow down a specific chip or pair if problems are found.

    5) Sometimes it helps to take a Q-tip with isopropyl alcohol and clean the contact pins of the chip. Do not use the alochol on any other part of the chip and make sure to give it sufficient time to make sure it is fully dried before installing to try again.

    Dust particles within the machine could also be a source of the problem so you can take a can of air and use it to blow the sockets and machine board free of the dust particles. You can normally get a can of air at most electronics stores or local Walmart type stores. I have even seen them carried in stores like Osco before.

    6) To make sure heat is not a factor in causing your machine problems if using a MacBook/MacBook Pro refer to the article we have posted about it .

    7) Try a full Logic Board Reset :
    a. Unplug the computer
    b. Open the machine
    c. Reset button.
    For more help on locating this button see .

    1)G4 or G5: Press and release the /PMU/S1 button like a doorbell ; a small silver button by the PRAM battery.
    2) G3 Hold the Cuda reset button for 7 seconds: ; a small silver button by the PRAM battery.

    d. Press the power button on the front of the machine 3 times, holding it for 1 second each time
    e. Remove the PRAM battery (looks like a half-sized AA battery) for an hour and a half.
    f. Put the PRAM battery back in, close the machine up, plug in the power cord, and start the machine.

    If there are still issues and you can get the machine to startup with the memory installed there are some software tests you can run.

    1) In OS 9 the option to run is Gauge Pro which is an excellent memory testing option. Go to here and download Gauge Pro to test the memory.

    a) Put the just the new chip in the machine by itself.
    b) Boot into 9 and run Gauge Pro 1.1 to evaluate the memory module.
    c) Hit CMD-M and run continuously
    -> Should accomplish about 100 to 150 passes
    d) If there is a problem, you will get an error message.
    e) Repeat this process for the other chips if you have purchased multiple chips.
    f) Keep track of which module is at fault according to the Gauge Pro software

    2) In OSX the software we recommend running is Rember. Go to and download Rember. This is an OSX program that can test the memory and is pretty accurate.

    3) You can get AppleJack from . This software needs to be installed in OS 10.2.x or higher. You then need to restart and boot to single user mode holding down Command(apple) and S. Once the screen comes up for AppleJack press the X key to enter E(x)perimental mode. It is not listed, but does exist. Then select the option for running Memtest. This has the advantage of leaving almost all the memory free for testing vs some of it being allocated for the system that the other two previous options require.

    4. You can boot to the disk that came with your system and run Apple Hardware Test(AHT) and use that to test the memory. G4 Macs and later distribute the Apple Hardware Test on a system disc that came with your machine. Each Apple Hardware Test is specific to the type and model of Mac with which it was distributed.

    To run the Apple Hardware Test, you must start up from the disc:

    a) If you have an Apple Hardware Test CD, start up from it as you would any other bootable disc:
    1. Insert the Apple Hardware Test disc that came with your Mac into your Mac's optical drive.
    2.Press and hold the C key on your keyboard as you start your system.
    3. Release the C key after the screen changes indicating it is loading.

    b) If your PowerPC-based Mac has an Apple Hardware Test volume on the Software Install and Restore DVD:

    1. Insert the Software Install and Restore DVD that came with your Mac into your Mac's optical drive.
    2. Immediately press and hold the Option key on your keyboard to reach the Startup Manager.
    4. Release the Option key after the Startup Manager appears on your display.
    5. When the progress indicator disappears select the Apple Hardware Test volume.
    6. Click the right-pointing arrow. Your Mac will continue to start up from the Apple Hardware Test volume.

    c) If you have an Intel-based Mac, see the Apple article found

    After you startup from the Apple Hardware Test, run the Extended Test.

    You may want to run the Extended Test several times in a row as sometimes intermittent problems don't show up on every test. You may want to run the AHT in Loop Mode overnight which can be an excellent troubleshooting step for finding intermittent hardware problems.

    If Loop Mode is supported by the version of the Apple Hardware Test you are using, you run the Extended Test in Loop Mode by pressing Control-L before starting the test. Looping On should appear in the right window. Then click the Extended Test button.

    The test will run continuously until a problem is found. If a problem is found, the test will cease to loop, indicating the problem it found. If you let it run in loop mode allow it to loop 50+ times to make sure no problems are found.

    You can stop the Extended Test and exit Loop Mode by either:

    a) Pressing the Command-period keyboard shortcut, i.e. Command-.
    b) Clicking the Cancel or Stop Test buttons. This can be difficult to do in Loop Mode.
    c) Manually restarting your Mac. Restarting manually, i.e. via either the power button, or if your Mac is so equipped,  the Reset button.

    Jon Gunnison
    Tech Support
    Other World Computing, Inc.
    2650 Bridge Lane
    Woodstock, Illinois 60098
    Sales & Customer Service (800) 275-4576
    International (815) 338-8685
    Fax (815) 338-4332

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