iMac (27-inch, Mid 2011)


macrumors newbie
Original poster
My apologies if this has been answered elsewhere my search didn't turn up what I was looking for.

I've inherited this iMac and I noticed that it's running 12 GB of RAM, 2-4GB slots, & 2-2GB slots for a total of 12 GB. I've searched for information on the max amount of RAM and have come up with conflicting information. According to Apple recommendations, 16 GB is the max whereas an article out of OWC claims that this particular model can run 32 GB of RAM, 4-8-GBs.

Has anyone upgraded a similar iMac to 32 GB?




macrumors newbie
Feb 21, 2019
Correct. 32GB (8GBx4) PC10600 1333Mhz DDR3. You can get the full 32 on amazon for about $150 or 16GB (8GBx2) for around $72. Make sure it’s compatible. A lot of sellers will tell you the models it works with.


macrumors newbie
Feb 17, 2019
I've tested my iMac 27" Mid 2011 with 24GB of Ram. 8GBx2 @1600Mhz in the first two slots and 4GBx2 @1333Mhz in the next two slots. It works without an issue!

However, I've now removed the 4GBx2 for the sake of not messing around with miss-matching ram frequencies and possibly even different voltages.

P.S : I was using a recommended Crucial Ram for the 4GBx2 config and a system-pulled Samsung ram for the 8GBx2 config.

Paulie Paulie Paulie

macrumors newbie
Jan 7, 2019
Just added OWC 8GB x 2; left in the 2GB x 2 giving me a total of 20GB. Makes a world of difference for an iMac that going on 8 years old. Next: upgrade the RAM on 2008 macbook. Trying to eek out some more time to see if iMac updated models come out this year.