I am soon to be getting a new 27” iMac with 4GB RAM (it has two, 2GB sticks).

The iMac accommodates four sticks. I would like to increase my total to 12 GB RAM, but am uncertain that would be wise.

I am thinking of getting 2, 4GB sticks from OWC and putting them in the other two free slots. Waddya think? Good idea or no?

Also, I do not know how/where the Apple RAM is installed. Is there a stick on both the left and right side, or are they both one side?

Should the new/OWC RAM merely be inserted in the empty slots, e.g, 4GB on one side and 8GB on the other, or is it best to have identical sides, e.g., a 4GB + 2GB on each side?

In Support article iMac (Late 2009) and iMac (Mid 2010): Installing or replacing memory Apple doesn't say anything about specific pairings, only that the i5 and i7 Quad Core models need at least one DIMM in any of the top slots. This suggest that you can fill up those slots pretty much any way you choose, provided the DIMMs meet specs. That said, I would leave the Apple DIMMs in the top slots, and put your OWC ones in the bottom.

Many thanks kind sir.

As much of this is magic to me, I wonder if the "larger" DIMMS should be in the top slots or if it (even) makes any difference. I don't see that it would, but, alas, there is much in life that seems intuitive to me, but it just ain't so.

Waddya think?

Frankly, I don't know, but based on the available info I'd say it doesn't matter.

Thanks again.