Pairing Memory: Match BANKs or DIMMs

[wdr1]

I purchased an additional 2 8GB ram sticks for my iMac. My intent was to upgrade the original 8GB (from Apple) to a total of 24GB.

When I opened the back, I noticed Apple had installed a 4GB slot in the 1st & 3rd slot. I thought that odd and would have expected it in the 1st & 2nd. I googled around to see where I should add my additional 8GB cards, but didn't come up with anything. So, I installed in the 2nd & 4th slot.

Should matching memory sticks be in the same BANK or in the same DIMM?

I.e., should the 4GB sticks be in BANK0/DIMM0 & BANK0/DIMM1 -- or -- BANK0/DIMM0 & BANK1/DIMM0.

 

[redheeler]

My iMac has the same arrangement. I think it's safe to trust the way Apple installed it.

 

[jerwin]

each bank should have 12 GB.

Install new sodimms in the empty slots (2 and 4.)