iMac Late 2012 RAM-Upgrade question

No one has take delivery of one of the new iMacs yet so it's impossible to say with total certainty. I'd recommend contacting OWC (www.macsales.com) via telephone and ask to see if they have some insight. While they may not know immediately I'm sure once the 27" iMacs ship they will know very soon after.

Am I missing something? I thought the new iMacs were not RAM-upgradeable and had to be done in the factory? Sorry if I've misunderstood!

You are correct for the 21.5" models as far as we can tell, the 27" models are another story and can be user upgraded from what we can tell. However again, because no one has taken delivery yet it's impossible to say with 100% certainty.

The new 21" iMacs are not ram upgradeable but the new 27" iMacs are ram upgradeable.

Yes. They specifically state on their site that this RAM is for the new 27 inch iMacs of late 2012:

http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=06ED3C48A5CA7304

This is probably so. Habs also read.

And so also these - are however more expensive:

Samsung 16 GB dual channel Kit 2 x 8 GB 204 pin DDR3-1600 SO-DIMM (1600Mhz, PC3-12800S, CL11)

I just installed two G.Skill DDR3-1600 PC3-12800 8GB cards. Works great http://www.gskill.com/products.php?index=565

Did you install in addition to factory RAM? I'm planning on adding 2x8GB in addition to the factory 2x4GB. I know you can expect better stability/performance by having all 4 chips the same size/brand, but I've never had an issue in the past using mixed pairs.

Hi

Yep. I left the original RAM and added the 2 new cards. So am running 24gb of RAM in total. Planning to upgrade to full 32gb but this is working fine

I'd recommend not upgrading the RAM until you are sure you need it, unless you are using apps that are incredibly RAM intensive chances are 24GB is plenty. To keep an eye on your RAM usage you can always run Activity Monitor, Apple discuses how to use AM in Activity Monitor to read System Memory and determine how much RAM is being used

I installed 16GB on top of the 16GB that my 27 inch i7 3.4 GHz came with.

It's a great improvement on the 8GB of RAM I had in my old iMac 🙂

I also upgraded my RAM to 16GB. What slots did you guys place them in? Sadly my new iMac came misconfigured with only 1 8GB card installed (in slot 2). The other 3 slots were empty. So now I want to install my 2 new aftermarket Corsair Vengeance cards and I'm not sure which slots to place them into. I currently have them in slots 2 & 4 - so it shows hoirzontally like this.

Is that what yours look like?

That is how it showed up when I ran the crucial app as well.

When I opened the iMac memory door / cage the actual memory is not laid out in the format.

The memory slots are all in a line parallel to each other, in effect stacked on top of each other With the slots filled in alternately. So as you looked at the memory it was like this:

Top slot - 8gb

Next slot down - empty

Next slot down - 8gb

Bottom slot - empty

I just added the two new 8gb sticks to the 2 empty slots.

You may find the crucial app does not really know which slots things are in, it just reports how many sticks there are.