Late 2015 27 iMac 5k RAM spec

So I just wanted to close out this thread. The Crucial memory has been back-ordered for months and I was finally able to get 2 x 32GB KIT CT2K16G3S186DM from B&H Photo and they are working great! Apple Diagnostics and Rember tests passed without any errors. I now have 64GB of usable RAM and no kernel panics.

So it looks like in my case the problem wasn't a quirky iMac but that the OWC memory didn't seem to be up to spec if you wanted to use all 64GB of RAM.

Curious as to why you think that may be overkill? I have a current MK482LL/A and I do music production but I can't even find working ram for this machine. The crucial sticks that matched caused system corruption but when they were working I could still barely get the system to keep up. Just my 2 cents and question. Thoughts?

I was reading some comments from people that they're running at 1600 but in my scenario I had some very odd issues happen. Basically fusion drive dissapeared, noticed in logs it was mentioning an overclock??? And the machine chose to "underclock due to power?" From there it was absolute corruption. When I say corruption I mean opening up system report and getting nonsense as pertaining to my system. The crucial ram did show up ok @1867 but shortly after that everything collapsed. Took it back to the vendor, they confirmed a system-wide failure after only two weeks, gave me a new machine, but at this point it's just sitting in the box. I'm a heavy musician and 8gb won't cut it for what I do. I've been told that the R9 M395 has some issues when dealing with 8Gb or larger...this is my first experience with Apple after years of flawless use on a Mac Pro in a major recording studio in Houston about 9 years ago and while a lot is the same, the things that were great then I just don't see now. I'm open to any suggestions. Reading up to it does mention that iMacs are not working well with stacked IC DDR3 SDRAM, and that it was designed to use non-stacked, but although TSV isn't new, to my knowledge no iMac is running any newer tech than HMT. At this point I'm stuck. Any help would be appreciated.

Late 2015 iMac MK482LL/A stock so 17,1 EMC 2834 3.3 skylake i5-6600 quad core 2TB Fusion AMD R9 M395 and stock 4Gbx2

Thanks.

I own the iMac17,1 (Late 2015) with a 4 GHz i7, 4GB Radeon M395X and 3 TB Fusion drive.

I created wish lists on the B&H and Crucial web sites and when B&H emailed me I pounced. I bought 4 x 16 GB crucial sticks (2 x 32 GB kits CT2K16G3S186DM) from B&H.

No problems since I bought the 64GB of RAM, I am able to use all of the memory to run apps and plenty of virtual machines.

At that as well, if you read up on system architecture and memory there are some very complex things to keep in mind, and I've never had a manufacturer that has not been able to give you information about their hardware, or a manual with part numbers, or tell you different configuration scenarios in depth, for example some machines run ran into a champ, some run ram in quad channel, some Ronit in what's called "ganged mode" and some do linking which is basically a type of game mode but a bit different where, for example on the iMac bank zero dimm zero and bank one dimm zero would be actually connected, and then when second set of identical ram is installed it would become dual channel,

I just ordered my New iMac last night. I've been shopping for ram and this is what I found.

http://eshop.macsales.com/shop/memory/iMac/Retina-5K2015/DDR3L

I wish Apple would official let us know that the new iMac can support 16GB per slot on the new 5K iMac

Can you still upgrade the RAM? Apple has been doing away with this with pretty much all their lines (Mac mini, MacBook) and from the pictures on the site I cant see the door on the back to add more RAM. Is there an official word on this?

ThePro PR wrote:

Can you still upgrade the RAM? Apple has been doing away with this with pretty much all their lines (Mac mini, MacBook) and from the pictures on the site I cant see the door on the back to add more RAM. Is there an official word on this?

The 27" is still user upgradable and says so int the tech specs.

Here are the specs:

iMac (Retina 5K, 27-inch, Mid 2015) - Technical Specifications

I wish Apple would official let us know that the new iMac can support 16GB per slot on the new 5K iMac

I've never seen or heard of a 16 GB module; the highest I've seen are 8 GB.

And, for The Pro PR - the RAM in the 27" models can be user upgraded:

iMac: How to remove or install memory - Apple Support

superunison wrote:

I wish Apple would official let us know that the new iMac can support 16GB per slot on the new 5K iMac

There are many Macs that work just fine on memory configurations "not officially supported".

The new 5K iMac is yet another (my early 2011 13" MacbookPro "officially" only supports

8 GB but has been running with 16GB for the last 3 years).

If you really want (and can afford it) get a full 64GB here:

http://eshop.macsales.com/item/Other%20World%20Computing/1867DDR3S64S/

ordered two 16gig modules earlier today. ordered the computer yesterday.

http://eshop.macsales.com/shop/memory/iMac/Retina-5K2015/DDR3L

Interesting - missed that when I looked earlier.

I pondered all day about buying the 32 gigs via 2-16gig modules. Very expensive at $599. At least I have the option down the road to order another 32 gigs when the prices go down. For now I'll have the 32 plus the 8gigs that will come with the computer.

Read my posts on this thread.