I have a weird problem on my mid 2013 27" imac. A few days ago, I started getting kernel panics and crashes every few minutes. After discarding software issues, I started testing the ram sticks. I have 2 sticks, 4GB each. I ran memtest and Apple diagnostics. Memtest gave a clean bill of health. I ran apple diagnostics individually for each stick, in every slot, and always came out OK. However, with the 2 sticks inserted (I tried all slot combinations several times), I occasionally got a memory warning.
I then took out one of the sticks, and ran my imac on 4GB. Worked perfectly for a week, no kernel panics.
I then re-inserted the ram stick, and Kernel panics again.
I am now using only the other ram stick, several days now, and again, perfect performance, no panics.
So it seems to me that the 2 sticks work fine, individually, but can't seem to work toghether. They are both identical, Elpida 4GB sticks that shipped with the imac.
Does anyone know if this is a RAM issue or a problem on my iMac? What should I do? I need my 8GB.
Thanks in advance,