iMac not recognizing both memory cards

I tried upgrading the memory in my Intel iMac with a Kingston 4GB memory kit (the ones they sell at every BestBuy in the country).

The original 1GB card works fine. It will work in conjunction with either of the two cards for a total of 3GB, so I know the cards aren't damaged. The two cards, however, will not work together. I have no clue what to do (other than just live with 3GB).

It's an Intel 2.4 GHz Core 2 Due and OS 10.4.11

Have you tried both 2gb cards in both slots? when u say the 2 GB cards will not work together - what shows in the profiler?

What year\model is your iMac? It may not be able to address 4 GB of memory. I'm thinking your machine is perhaps a late 2006 model? If so, you can install 4 GB of memory, however, only 3 GB will be addressed.

Also, buying memory from Best Buy is not the most economical way. On line sellers like Crucial or OWC have much better prices and they also have complete specs on how much memory and what kind your iMac uses.

Regards.

Is this your machine Apple iMac "Core 2 Duo" 2.4 20-Inch (Al) Specs (Mid-2007 - MA877LL) @ EveryMac.com ?

Collin Bl said:

Is this your machine Apple iMac "Core 2 Duo" 2.4 20-Inch (Al) Specs (Mid-2007 - MA877LL) @ EveryMac.com ?

Click to expand...

That is my machine.

With both cards in, it won't boot up. Got this desktop in mid 2007, just before OS 10.5 came out.

Ok so if u put a 1 and a 2 in it will boot but what shows in the Profiler - try it for both the 2 GB units one after the other with the 1GB on board making sure you mark the chips so u can recognise which is which later.

Collin Bl said:

Ok so if u put a 1 and a 2 in it will boot but what shows in the Profiler - try it for both the 2 GB units one after the other with the 1GB on board making sure you mark the chips so u can recognise which is which later.

Click to expand...

I tried that to make sure both cards where ok. The machine boots fine and the profiler shows 3GB. Both cards work with the original card, but won't work together. I exchanged them to make sure it wasn't some kind of crazy fluke and got the same result. I tried switching the cards around in every way possible; they simply will not work together.

Mr.Jowee said:

I tried that to make sure both cards where ok. The machine boots fine and the profiler shows 3GB. Both cards work with the original card, but won't work together. I exchanged them to make sure it wasn't some kind of crazy fluke and got the same result. I tried switching the cards around in every way possible; they simply will not work together.

Click to expand...

You need to give us the exact machine ID and\or model. Your machine is very likely a model that can only accept 3 GB of memory. Putting 2 x 2 GB modules may work, and again may not. According to the Apple specs, it doesn't matter since only 3 GB will be addressed anyway.

Since you swapped the original modules for new ones and still can only put a single 2 GB module in at a time with the 1 GB module it would appear that your machine is limited to 3 GB.

Regards.