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  1. #1


    Member Since
    Aug 07, 2008
    Posts
    3
    Mac G5 won't boot with New memory
    Machine Name: Power Mac G5
    Machine Model: PowerMac7,2
    CPU Type: PowerPC 970 (2.2)
    Number Of CPUs: 1
    CPU Speed: 1.6 GHz
    L2 Cache (per CPU): 512 KB
    Memory: 2 GB
    Bus Speed: 800 MHz
    Boot ROM Version: 5.1.5f2

    I currently have 2 GB ram as you can see from my computer specs. They are 4 512MB ram chips that are paired memory. So I'm trying to take 1 pair out and put 2 UNPAIRED 1 GB chips in there making a total of 3 GB but my computer will not boot. Let me share the specs of the ram i have then give more details.

    Current Ram:
    2 x 512MB Unbuffered PC2700 CL2.5 from Apacer
    2 x 512MB KVR400X64C3A/512 from Kingston

    New Ram:
    1 GB DDR 400, CL3 PC3200U from Aeneon
    1 GB 184-PIN UNBUFF DIMM from Crucial

    The Crucial 1GB chip is confirmed MAC compatible from Crucial themselves. The Aeneon chip is supposed to be MAC compatible but I can't get a confirmed answer on that.

    I've tried every configuration I could think of. Strange thing is the system will not boot with just 1 pair of ram in the system by itself. (ie. Just the 2 Kingstons or just the 2 Apacers). It will not boot with just 1 chip of either the 1GB.

    WHEN I SAY IT WONT BOOT, I MEAN IT POWERS UP BUT NO CHIME AND POWER LIGHT JUST BLINKS.

    I pressed S1 inside the case to reset PVRAM but I can't do any of those "command + option...." tricks because system has to actually boot for that to be used. I've tried all 4 slots with just 1 chip in it.

    Conclusion Thus Far:
    Only setup that will work is with both sets of paired ram installed.

    Other notes:
    I would of gotten 2 Crucial chips but I didn't have the funds. The Aeneon was cheaper at a different store and I had funds to get 1 Crucial and 1 Aeneon. But that shouldn't matter.
    The fact that 1 chip is PC3200 and one is PC2700 doesn't matter. Crucial's memory configurator says I can use either PC2700 or PC3200. Crucial rep confirmed I can use both at same time.

    Any help would be greatly appreciated.

  2. #2

    kahlil88's Avatar
    Member Since
    Jan 29, 2008
    Location
    Mendocino, CA
    Posts
    682
    Specs:
    17" MacBook Pro A1297 2.3 GHz i7 4GB DDR-1333
    It might not like the RAM - could be bad or maybe incompatible. I would try re-seating it and maybe even blowing any dust out of the slots.
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  3. #3


    Member Since
    Aug 07, 2008
    Posts
    3
    I dusted it all out. And I know the Crucial RAM IS compatible. The Aeneon RAM is supposed to be compatible.

    But that doesn't explain why just one pair of the working ram will not allow the system to boot either.

    The only way I can get it to boot is if BOTH PAIRS of RAM is in there.

  4. #4

    hughvane's Avatar
    Member Since
    May 18, 2008
    Location
    Banks Peninsula, Canterbury
    Posts
    3,326
    Specs:
    MacMini 4.1, OS 10.11 and 10.6; Macbook Pro 8.2, OS 10.11, MacBook 4.1, OS 10.6.8
    Quote Originally Posted by swg1cor14 View Post
    I dusted it all out. And I know the Crucial RAM IS compatible. The Aeneon RAM is supposed to be compatible.
    But that doesn't explain why just one pair of the working ram will not allow the system to boot either.
    The only way I can get it to boot is if BOTH PAIRS of RAM is in there.
    What's the minimum RAM req'd for that model of G5?

    Workaround (maybe):
    1. Put all the old RAM sticks back in.
    2. Boot up your G5, get everything running tickety-boo (if poss).
    3. Open Activity Monitor. See what's happening with memory there. Compare Used with Free to see if it totals the physical RAM (ignore VM).
    4. Open System Profiler - check physical memory to see if all sticks are being read and utilised.

    4 RAM slots - right? You want to go to 2 Gb RAM total. Have you considered getting two more of those 512MB KVR400X64C3A/512 from Kingston, (assuming they're working okay via the checks above)? 4 x matched RAM sticks would be my choice.

    From what you've posted, it reads as though there's RAM incompatibility involved. There are simple RAM check software programs available, MemTest is one (Google for others).

    As kahlil88 says, it may not be a RAM problem. Check all other cards inside your G5 (assuming it's a tower model), make sure they're seated right. You've been opening up that G5 to replace/reinsert RAM quite a bit, something may have been dislodged.

  5. #5


    Member Since
    Aug 07, 2008
    Posts
    3
    No. Maximum Ram for this system is 4GB. Which I am trying to accomplish that. Right now I only have enough to make 3GB. (2x 1GB chips and 2x 512MB chips (Paired))

    I can't boot system with new ram AND old ram installed. I tried BOTH these new ram chips in another mac and it won't recognize them either. I will ship this ram back and get new.

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