I have a late 2013 27-inch iMac with 8G DDR3-SDRAM. I would like to upgrade my RAM. Can I add two 8G (16G total) RAM with the two 4G (8G total) RAM already installed for a total of 24G or do I have to keep the RAM the same in all four slots? i.e. Four 4G RAM cards or four 8G RAM cards? Thanks.
iMac, OS X Yosemite (10.10.2)
It is not necessary to match pairs with memory, but it will run better if you do. On the store website they were only configurable from 8 GB to 16 GB or 32 GB.
Read the user manual on RAM installation that came w/your iMac and/or read the KB Article iMac: How to remove or install memory
No, my iMac has 24GB and runs perfectly, it has for the past 2 years.
What the sequence of modules installation? 4-4-8-8? 8-8-4-4? Or 8-4-8-4, 4-8-4-8? Thank you.
You are making this WAY too complex, simply install the RAM into the empty slots and get on with it.
i've read something about the performance reduce after the incorrect installation of the two-channel memory. and in some scenarios mac does not boot up.
I'Ve read this article many times and there is no one word about the installation of different memory size RAM modules.
You can install the ram in any of the 2 empty slots. It can be just one or two doesn't have to be in pairs. Go for the max if you can.
Late 2013 27 inch iMac Upgrading RAM
