Why wont this Ram stick work?

Discussion in 'Mac Basics and Help' started by Josh2022, Sep 10, 2005.

  1. Josh2022 macrumors member

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    Aug 16, 2005
    #1
    My friend gave me 2 512MB sticks out of his computer (Non Mac) because he is buying a new one...

    One is a Crucial PC2100U-25330-Z -- 512 MB, DDR, 266MHz, CL2.5

    The other is a Infineon PC3200-30330-B0 -- 512MB, DDR, 400, CL3

    Neither register when i turn my mac back on, why? i think atleast one should work. is there something i have to do in mac like tell it i am adding ram in another slot or something? I only have 1 slot open.. i have 3 1GB in the 3 other DIMM slots that came from my local apple store, they put them in..

    What should i do?
     
  2. belvdr macrumors 601

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    Aug 15, 2005
    #2
    Without the specifications of your Mac, there are numerous things that could cause it not to work. Specifically, your Mac may not use DDR RAM or it could be too slow or it could be that your other RAM is ECC. What does one of the 1GB sticks say?
     
  3. Josh2022 thread starter macrumors member

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  4. iGary Guest

    iGary

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    #4
    Do you have 4 DIMM slots or 8?
     
  5. Josh2022 thread starter macrumors member

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  6. iGary Guest

    iGary

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    #6
    These are the specs if you have 4 DIMM's:

    Module Size: 2GB kit (1GBx2)
    Package: 184-pin DIMM
    Feature: DDR PC3200
    Configuration: 128Meg x 64
    DIMM Type: UNBUFFERED
    Error Checking: NON-ECC
    Speed: 400
    SDRAM Timings: CL=3
    Specs: DDR PC3200 • CL=3 • UNBUFFERED • NON-ECC • DDR400 • 2.6V • 128Meg x 64
     
  7. Sun Baked macrumors G5

    Sun Baked

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    #7
    The PowerMac G5 is dual channel (requiring matched DIMMs installed in PAIRs).

    Those aren't matched pairs -- because one doesn't even meet the minimum specs for the machine in the first place.

    The match doesn't have to be exact, but you need at least the minimum specs.
     
  8. iGary Guest

    iGary

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    #8
    So that's why you won't see it.

    Macs are uber-finicky when it comes to RAM.
     
  9. belvdr macrumors 601

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    #9
    Dual channel is a different technology regarding performance. I think you mean it has 2 banks of 2 sticks.
     
  10. Josh2022 thread starter macrumors member

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    #10
    mhmm.. well that really sucks, lol. I really wanna get atleast 512 More ram in my computer, i have like 17 programs open atm and i hate closing some to play WoW or something.. yeah im lazy. >.<
     
  11. CanadaRAM macrumors G5

    CanadaRAM

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    #11
    OK Josh: First Newbie rule is you gotta tell us what Mac you have...

    By inference, since you have 3 of 4 slots filled by the Apple seller, it can't be a PowerMac G5 tower (requires paired RAM), an iMac, 'book or eMac.

    That leaves a G4 tower -- now if the PC2100/3200 RAM modules physically fit, it can't be a PC133-based machine it must be newer than a Quicksilver, so we'll postulate it is a Mirror Drive Door G4. BUT: the G4 MDD doesn't take 1 Gb modules, they have a maximum of 2 GB with 4 x 512 Mb.

    So if you have a G5 with 3 x 1 Gb RAM in it you are seriously messed up because the RAM has to be paired.

    If you have a MDD G4 with 3 x 1 Gb RAM in it you are messed up because it doesn't take 1 Gb modules. http://www.apple.com/hardware/powermacg4/specs.html

    MDD machines require either PC2100 or PC2700 RAM depending on what the speed of the CPU is. If it is the 1 GHz Dual or 1.25 GHz or up in speed, then that PC2100 is not gonna work. In any case, the RAM has to be Mac-compatible RAM. There's no way of telling whether the PC RAM you are trying has the SPD values programmed correctly for Mac.
    You do not have to make any 'BIOS' or setting changes on a Mac.

    Of course, it may be as simple as you are not pushing them far enough into the socket. Or the RAM is damaged or defective.

    So the final answer is: HTH would WE know?

    How about you post a screen shot of your About This Mac dialog, and maybe one of the Apple System Profiler data on the RAM???

    Edit: Aw Hell, guys. How come you type so much faster.... ;)
     
  12. CanadaRAM macrumors G5

    CanadaRAM

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    #12
    Ummm.... how much RAM DOES your machine register -- Should be 2 Gb if you have 3 x 1 Gb modules in.

    Go back to the Apple dude who let you take the machine out of the shop with 3 DIMMs in it, and punch them in the nose :D
     
  13. Josh2022 thread starter macrumors member

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    #13
    Ok here is what it is, I have 3 1GB Sticks in my computer, I have 4 DIMM Slots. My machiene registeres 3GB of the 3GB. Im using a powermac G5, and I know the ram isnt bad because it was working fine when my friend took it out of his computer for me, it want into 2 plastic ram containers. With all your help, i see that the PC2100 one will Not work, but shouldnt the PC3200 one work? IDK. This ram is so tricky in macs, lol. I think i answered all the questions?
     
  14. CanadaRAM macrumors G5

    CanadaRAM

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    #14
    It doesn't work because you have 2 pairs of memeory sockets -- you ned to have equal pairs of modules in the two sockets of a pair. 1 Gb + 1 Gb or 512 + 512 --- NOT 1 Gb + 512
    I am suprised all to #=!! that the machine is recognizing that lone 1 Gb module at all.
     
  15. Sun Baked macrumors G5

    Sun Baked

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    #15
    Dual-channel is the technology that is basically 2 banks of 2 sticks.

    The iMac G5 will operate in either single/dual-channel mode depending on the DIMMs you stick in the 2 slots -- but, the PowerMac G5 will not.

    This is where the thread starter is running into trouble.

    Putting a 1GB DIMM and a 512MB DIMM in a single PMG5 memory bank ... it's recognizing the 512MB DIMM as broken most likely, and turning it off.

    Of course the AppleStore fool that only put 1 DIMM in a PMG5 bank does deserve that punch in the nose.
     
  16. Josh2022 thread starter macrumors member

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    #16
    Dont ask me, ask the guy at the mac store, lol. Im going out to dinner, ill ask my brothers friend when im done work tonight, he works at my local apple store.
     
  17. belvdr macrumors 601

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    #17
    Actually, it appears it can be either mandatory or an option, depending on the system. It's a shame that the same terms are used differently all over the place.

    See here

    For example, my Asus A7N8X Deluxe motherboard utilizes dual channel. However, it only does so when matched sticks of RAM are in slots 1 and 2. You can still run it with only one stick of RAM. When you have matched sticks and run in Dual Channel mode, it read/writes to both sticks at the same time, increasing performance.

    Now, on the Dual G5, Crucial says it has "2 banks of 2", which means it requires matched sticks.

    Dual channel, 2 banks of 2, whatever.. If this G5 is recognizing 3 sticks of 1GB as 3GB of RAM, I wonder if the G5 actually requires RAM to be installed in pairs or if this person is just lucky it is running.

    EDIT: FYI, I was just explaining my stance, not saying you are wrong. The whole computer terminology is beginning to get confusing no matter what you do.
     
  18. Artful Dodger macrumors 68020

    Artful Dodger

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    #18
    At first when I read this I thought I "really" could use some coffee but then I went back and read this again and only one question left for this...
    Can you have a picture of this posted/screen shot maybe? I know you say you have a G5 but what a memory mess in there :eek:
     
  19. Josh2022 thread starter macrumors member

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    Aug 16, 2005
    #19
    Ill post a picture in a bit, but just forget it im happy with the memory i have and if i do replace something ill probably blow my computer the hell up or something knowing my luck.
     

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