13 Replies Latest reply: Jan 28, 2009 9:50 PM by Yvon Couture
Yvon Couture Level 1 Level 1 (65 points)
Hello, I recently bought 16GB of RAM from OWC. Everything was fine for about 1 week. Then I started to get all king of crashes and, more specifically, kernel panics. In about 1 year and a half the computer was totally stable with the standard apple 1 GB.

I've tried a lot of different combination and my conclusion is that if I only put in 8 GB of RAM the mac pro is TOTALLY stable.

Have anyone else experience this? I wish I could use the f

Mac Pro 2.66, Mac OS X (10.4.9)
  • 1. Re: MOre than 7 GN of RAM
    marokero Level 1 Level 1 (135 points)
    Have you tried reseating each memory module, and/or shuffling them around (since I assume they are all the same exact module)? I also bought 16GB of ram from OWC, and at first things worked well, then on the second time I reboot System Profiler told me I had only 12GB instead of 16GB. I reshuffled the modules around and never had a problem since - it's been 7 months already. Hope that helps.
  • 2. Re: MOre than 7 GN of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    I had the same expience too. Like one of the crash, and don't ask me why, it rebooted automatically, and it showed 12 GB. I'll try your suggestion. That's my next step.
  • 3. Re: MOre than 7 GN of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    The only thing I was worried about is that I took the cheapeast memory available from them. Should I have bought the more expensive one?
  • 4. Re: MOre than 7 GN of RAM
    marokero Level 1 Level 1 (135 points)
    Which memory set did you get, the 4x4GB or 8x2GB? I bought the later. If shuffling the modules around doesn't do anything, perhaps you can exchange them since OWC offers a lifetime replacement warranty.
  • 5. Re: MOre than 7 GN of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    I bought 8 X 2. I already email OWC. I'm waiting for their answer For years I bought things from them and it's the first time I run into problems. That memory mishap reminds me of my old dual 1.42 G4 that would crash all the time with kernel panick.

    Tomorrow I will test new ordering of the memory. Now with 8 GB no crash in 3 days. I really need the 16GB because I use a lot of sample in Logic Pro.
  • 6. Re: More than 8 GB of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    Today I shuffled the modules around. Now the system only sees 12 GB out of 16. Riser A slot 3 and 4 were reported as empty. I the shut down the Mac Pro and switched the cards. I mean I put the lower one on the top slot and the top one at the bottom. After restarting the computer the system still sees only 12 GB, but this time on Riser B slot 3 and 4.

    Is that an indication that that riser card is deffective?
  • 7. Re: More than 8 GB of RAM
    marokero Level 1 Level 1 (135 points)
    Try switching the modules on those slots. That's almost exactly what happened in my case. If all fails, contact OWC for replacement.
  • 8. Re: More than 8 GB of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    After a few restarts and reshuffling only the lower riser modules the system now sees all 16 GB. However, I still need to see if it will start having those kernel panics again. If it does I'll leave riser B slot 3 and 4 empty to see if it's stable at 12GB.
  • 9. Re: MOre than 7 GN of RAM
    Network 23 Level 6 Level 6 (11,690 points)
    Yvon Couture wrote:
    The only thing I was worried about is that I took the cheapeast memory available from them. Should I have bought the more expensive one?


    That is probably not a guaranteed cause of the problem. I also took their cheapest Mac Pro memory and it's been running flawlessly for over 2 years.

    If you got a bad RAM stick, it was simply the luck of the draw, not because you bought their cheapest.
  • 10. Re: MOre than 7 GN of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    Thanks, I now suspect the riser card also. In any case I'll see if it crashes again. Usually those kernel panics happen within 2 or 3 hours. At 8GB with any of the modules I bought the system was rock solid.

    I'm crossing my fingers.
  • 11. Re: More than 8 GB of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    Well... it's been a day without a crash. Shuffling the module and re-sitting them seems to have work so far.

    Thanks
  • 12. Re: More than 8 GB of RAM
    marokero Level 1 Level 1 (135 points)
    Glad things have worked out.
  • 13. Re: More than 8 GB of RAM
    Yvon Couture Level 1 Level 1 (65 points)
    So far so Good. 4 Days without a kernel panic, 2 restarts and all 16 are still being recognized. I'll see on the longterm, but untill now it seems ok and I am happy.

    Thanks!