iMac memory upgrade not working properly

Kilobyte Kid

iMac memory upgrade not working properly

Just received a Crucial 4MB Kit (2 x 2MB,  #CT717420) to upgrade my iMac from installed 1MB. Computer will not boot if either 2 MB chip is alone or both are together, no matter how you switch the slots. If I keep the original 1MB chip in I can place either one of the other two in--either slot--and it will boot, giving me a total of 3MB. The scan says I have a 4MB max. What gives?


I chatted with a customer service rep prior to my purchase and was guaranteed 4MB would work.  I have seen a couple of other recent posts with the same general issue (iMac and MacBook) though no solutions posted as yet.


Here are my specs according to the scanner (Scan Id: 9A62F70731D926C3)


 iMac 2.0GHz Intel Core 2 Duo (20-inch) MA876LL (OS 10.6.1)

# Maximum Memory Capacity:  4096MB
# Available Memory Slots:  2
# Total Memory Slots:  2
# Dual Channel Support:   No
# CPU Manufacturer: 
# CPU Family:  Intel Core 2 Duo 2 GHz
# CPU Speed:  2000 MHz


Here are specs from System Profiler:


  Model Name:    iMac
  Model Identifier:    iMac7,1
  Processor Name:    Intel Core 2 Duo
  Processor Speed:    2 GHz
  Number Of Processors:    1
  Total Number Of Cores:    2
  L2 Cache:    4 MB
  Memory:    3 GB
  Bus Speed:    800 MHz


ECC:    Disabled

  Size:    1 GB
  Type:    DDR2 SDRAM
  Speed:    667 MHz
  Status:    OK
  Manufacturer:    0x2C00000000000000
  Part Number:    0x3848544631323836344844592D3636374531
  Serial Number:    0xDD1AFDBA

  Size:    2 GB
  Type:    DDR2 SDRAM
  Speed:    667 MHz
  Status:    OK
  Manufacturer:    0x2C00000000000000
  Part Number:    0x3136485446323536363448592D3830304531
  Serial Number:    0xDD61ED4D


Thanks for any help,



Tags (1)
5 Replies
Bit Baby

Re: iMac memory upgrade not working properly

I just got 4 gb from Crucial today and am having the same problem with a similar I mac  (2.4GHz).  It will not boot with both sticks of 2 GB but will with either one of the 2 GB and the original 1 GB. You can see my info is similar except my original ram manufacturer is different.  (note same part number on Crucial RAM)


 Model Name: iMac

  Model Identifier: iMac7,1

  Processor Name: Intel Core 2 Duo

  Processor Speed: 2.4 GHz

  Number Of Processors: 1

  Total Number Of Cores: 2

  L2 Cache: 4 MB

  Memory: 3 GB

  Bus Speed: 800 MHz

  Boot ROM Version: IM71.007A.B03

  SMC Version (system): 1.21f4


Memory Slots:


  ECC: Disabled




  Size: 1 GB

  Type: DDR2 SDRAM

  Speed: 667 MHz

  Status: OK

  Manufacturer: 0xAD00000000000000

  Part Number: 0x48594D503531325336344350382D59352020

  Serial Number: 0x0000303C




  Size: 2 GB

  Type: DDR2 SDRAM

  Speed: 667 MHz

  Status: OK

  Manufacturer: 0x2C00000000000000

  Part Number: 0x3136485446323536363448592D3830304531

  Serial Number: 0xE14FE926



Please let me know if you figure this one out.



Kilobyte Kid

Re: iMac memory upgrade not working properly

Hey Don,


Looks like there are lots of similar posts out there regarding the same issue we are experiencing. Here is one for instance:


These people are being told by the moderators that they need to place a replacement order  for "a different component build" . I suppose I will wait to see if we get the same response...






Re: iMac memory upgrade not working properly

I am sorry to hear that you ran into this problem as well. Replacing these parts with a different component build is the best way to ensure that the problem is resolved by one single exchange. The reason we are asking you to contact Customer Support directly for that is because the RMA form on the website is processed automatically and since there are no humans involved in that process we can't guarantee that the system sends you a different build.


Fortunately, our Customer Support department can. When you contact them, mention what I posted in the other thread, that you need a different component build on the replacement order. They will take care of all details.

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Bit Baby

Re: iMac memory upgrade not working properly

I got a site recommended 3 GB upgrade for a 2.16 GHZ iMac. when I installed it, I have the same issue, no boot.  When I put the original back in, same thing.  Even the 1 GB that came with the iMac originally will not boot the computer.  Any suggestions?

Bit Baby

Re: iMac memory upgrade not working properly

t back from the Apple store where my hard drive is no longer operating.  Worked fine before I used the crucial memory upgrade, now it is done, is being replaced on warranty thank goodness.  Says nothing for all the data and programs lost.  DON'T USE iMAC MEMORY FROM CRUCIAL.  My hard drive was making a clicking, squeeking noise, so if you have that already, beware!