iMAC won't boot after RAM upgrade

Bit Baby

Re: iMAC won't boot after RAM upgrade

I'm encountering the same issue as some who have replied here.  If I use both 2G sticks it won't boot, regardless of which stick I put where, but if I use my old 1G stick and one 2G stick, it works.  Any idea why and how to get around it?  After all, I bought two 2G sticks and would much prefer 4G of RAM to 3G.

Crucial Employee

Re: iMAC won't boot after RAM upgrade

Hi Prongs1977,


I'm sorry to hear that you are having issues with your iMac memory.


First of all I would recommend  trying each of the 2GB modules one at a time in the system with no other memory installed.  This is the best way to check that both modules are working and that you don't have any fault with any of the modules.


There are however iMac systems which do only support 3GB and not 4GB as standard.  Could you please confirm the systems processor speed and screen size and I can look in to this for you?

Crucial_Junket, Crucial Moderator, UK

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Bit Baby

Re: iMAC won't boot after RAM upgrade

I'm hving the same trouble. My mack is a 24" 2.4GHz intel core 2duo Memory: 1 GB 667 MHz ddr2 sdram


Is this model only able to go up to 3 gigs?


Bit Baby

Re: iMAC won't boot after RAM upgrade

I just got through two hours with customer service on this issue, and I am reording new RAM. I think the first problem is that when going through the compatibility tool drop-down menu, for some models it may recommended the wrong RAM. When I found my exact specs:  iMac 2.8 GHz intel core2 duo (24 inch 800mhz), it directed me to an 800mhz RAM memory versus the 667mhz frequency. If you use one of your old 667mhz and one of the new 800mhz it will 'clock down' the new one to 667mhz and show 3GB of RAM -- fooling you into thinking that the RAM is OK and you bought the right product, BUT if you put both 800s in, then it won't work. You have to have one correct RAM in for the 'clocking' down to work apparently.  So on one hand the tools that they have may be stearing people to the wrong frequency of RAM, BUT to give Crucial credit, they do have a warning to double check the frequency on the RAM before ordering -- which I did not. Apparently the best way is to do the system scan, but I hate downloading stuff. When I eventually did the system scan, it says I have the core 2 extreme and not the core 2 duo (which my mac says I have). There was my problem. I guess I will see if it works when I get the new RAM  next week.