2 ram sticks not working toghether 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,

Albert C.
I would start with blaming the RAM. If it is possible to return both of them and get a replacement, I would do that.

The only way to tell if it is the RAM or the slot is to try different RAM. The problem with that is if you show up at an Apple store with 3rd party RAM installed saying that you have a bad slot, they will take out the 3rd party RAM and say "problem solved."

One option is to return the RAM for a refund and buy new RAM from another vendor, but if it fails you'll likely get a similar reaction from an Apple Genius.

It's a bit of a Catch-22 unless you can get an Apple genius to test your Mac with some Apple branded memory. Not sure if that is possible or not.