2009 mac pro ram question?

Discussion in 'Mac Pro' started by CapnDavey, Sep 21, 2016.

  1. CapnDavey macrumors 6502


    Apr 11, 2015
    I bought 16 gig of r dimms
    server ram I put it in replacing the U dimms it gave me a reboot with a error is the ram bad or did I need to reset the p ram?
  2. X--X macrumors 6502

    Jun 11, 2015
    Every time you change the hardware config, you should reset pram with "Command + P + R" on startup. That will probably solve it.

    If a module is bad I would try taking out one module after another and try rebooting until it works. That why you'll know which one is broken.
  3. h9826790 macrumors G5


    Apr 3, 2014
    Hong Kong
    When testing the RAM stick one by one, you may blow all the dust away from the slot as well.

    In my own experence. There is no need to do PRAM reset after RAM config change. However, quite a few members here report that a PRAM reset fix their RAM issue (especially wrong RAM speed). So, unless you are running a unflashed Maxwell GPU. Or still using the old method in Yosemite to activate TRIM. Reset PRAM should not cause any damage / trouble. Always worth a try before other trouble shooting.
  4. CapnDavey thread starter macrumors 6502


    Apr 11, 2015
    Thanks guys this is the first time I've ever had a ram issue some of the ram must be bad I will find someone with a ram tester then send the bad stuff back sucks oh well
  5. -VoiceOfReason-, Sep 25, 2016
    Last edited: Sep 25, 2016

    -VoiceOfReason- macrumors member

    Apr 27, 2010
    There is some simple troubleshooting you can do before returning.

    Remove all the RAM from the system. Take two RAM modules and insert them according to this image:


    Start the system and see if it will boot. If not, try two different modules. If it will again not boot, then you may have some kind of incompatibility going on.

    If it will boot, add two more modules and try starting the system. Repeat until you either have all modules in use or until you are no longer able to boot.

    Using this trial and error approach, you should be able to find the bad module (if one is indeed bad). If the system ends up booting with all RAM in place, consider running a memory test.

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4 September 21, 2016