Adding memory to new iMac

Hi All

I have just received my new iMac which came as standard with 4Gb RAM. (I believe this is 2 * 2Gb memory cards). I have ordered and received a further 8 Gb (2 * 4Gb) from Crucial, with a view to take my new machine up to a healthy 12Gb of RAM.

I was about to install the memory this afternoon so decided to look up 'How To' videos on Youtube. The reason for this post is that one of the videos mentioned that the memory should be paired the same size otherwise it will not take advantage of the dual channel aspect of the memory.

Does this mean if I have a mix of 2Gb Simms (2 * 2Gb) and 4Gb (2 * 4Gb) in the four memory slots that memory performance will be slower . If that is the case may be I should just add the 2 * 4Gb and remove the 2 * 2Gb leaving me with an 8Gb machine.

Help would be appreciated.

Cheers

No, it means they should be installed as matched pairs in the SAME bank. You already have 2 x 2 GB modules in the upper bank. Just leave them there. Place the 2 x 4 GB modules in the lower bank. The larger modules really should go in the upper bank for maximum efficiency and speed, however, removing and inserting modules in an iMac requires quite a bit of "thumb" effort, so it's best to leave the smaller modules where they are. I don't think it will make that much difference anyway.

You might want to use a cloth or small towel (or even gloves) to help push the modules in place. (To save your thumbs.)

chscag said:

No, it means they should be installed as matched pairs in the SAME bank. You already have 2 x 2 GB modules in the upper bank. Just leave them there. Place the 2 x 4 GB modules in the lower bank. The larger modules really should go in the upper bank for maximum efficiency and speed, however, removing and inserting modules in an iMac requires quite a bit of "thumb" effort, so it's best to leave the smaller modules where they are. I don't think it will make that much difference anyway.

You might want to use a cloth or small towel (or even gloves) to help push the modules in place. (To save your thumbs.)

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Yet more fantastic advise from this great forum !!! Thank you very much, you have put my mind at rest. Following your note I installed the new memory this morning. Just booted up the iMac and it recognises the new memory so now on 12Gb.

You were right about the thumb effort !!!!

Thanks again