

The confusing thing is that the graphics in About this Mac still shows them arranged the way they used to be (which makes no sense whatsoever). On the new iMacs, the slots are arranged vertically the "matching" needs to be slots 1 and 3, and/or 2 and 4. The slots used to be two rows with two slots next to each other and you matched two modules horizontally. You've certainly tried a lot of configurations my comment here would be to address the new configuration of the slots in the new iMacs. Is there a possibility that the Bank0=16GB and Bank1=4GB is the culprit? They were the original memory in the mac mini and I had no problems with them there. My diagnosis is that the 2 2GB DIMMs are bad. It's been running without problem for longer than any other iteration. I have now removed the 2 2GB DIMMs from the iMac and put the 2 8GB DIMMs such that my configuration is now:

I changed the memory installation configuration to this to put match pairs of DIMMs in Banks.At least it wasn't the blue screen of death 🙂 but only because it wasn't blue. While I wondered about this, the machine crashed. This is not optimal, and I wondered if it could be causing the problem. I discovered the system report and found that I had the following configuration: However, in short order I had an application crash-never happened before.

I installed the two 8GB DIMMS in slots 1 and 3 and the 2 2GB DIMMs in slots 2 and 4.
