Does iMac accept 64GB of RAM?
iMac with Retina has 4 SO-DIMM slots. Did you tested it with 8GB SO-DIMM? Does he accept it? 64GB — possible or not?
Model A1419 / EMC 2806 / Late 2014 or Mid 2015. 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (ID iMac15,1); EMC 2834 late 2015 / 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (iMac17,1) All with Retina 5K displays
Guys! Save your money and just purchase the 32GB RAM.
I purchased a brand new iMac 5K about a month ago from Apple and went ahead and purchased 64GB RAM upgrade from OWC and have been getting many kernel panics when rendering. I took my computer in to the genius bar and concluded it was a RAM problem. Contacted OWC for a replacement. I had also returned the iMac just because I was within the return policy (they recommended me). I got all brand new items again and gave it a shot and same thing. Was getting a lot of kernel panics during rendering in either FCPX and DaVinci Resolve. Again, I contacted OWC and they gave few troubleshooting steps and nothing worked. I ended up going back with the stock 8GB RAM it initially came with and problem solve. This has been a complete waste of time and money. I strongly don't recommend buying 64GB RAM.
Save your time and Money.
The first iMac 5K supports 32 GB max. The iMac 5K late 2015 supports up to 64 GB .
Would you need that much RAM? Most users not. Music & video editors do, graphics design professionals do. When I make a 400+ pages book in InDesign with over 900 images 16 GB of RAM just isn't enough. It's impossible. I tried, either the OS or InDesign crashes. 32 GB is great. Also with 32 GB of RAM most of the time there is no need for memory compression or need to swap which improves performance greatly, especially on older systems.
I use a late 2009 iMac 27" i7 with 32 GB of RAM which I will retire in the next year.
And on Amazon you can now buy 64GB memory kits for the 27" Retina iMac from PACCOM at only $729
Search for PACCOM 64GB iMac on Amazon
Watch out: These 64GB only work in the newly released October 2015 models of 27" iMacs with Skylake processor
64 Gigabyte RAM Kits for the newly released iMac 27" with Skylake processor are available at $729 on Amazon (click) for the complete kit of 4 x 16GB modules.
Watch out: These will not work on older models of iMacs and fit only in the 27" machines.
According to Apple my early 2011 MacBook Pro only supports up to 8GB. I've been happily running it with 16GB for years now without issue. That said according to Intel's i5-4690 and i7-4790K specs the maximum supported memory is 32GB.
More details in the datasheet: "Using 4Gb DRAM device technologies, the largest system memory capacity possible is 32 GB, assuming Dual Channel Mode with four x8 dual ranked DIMM memory configuration". See also an Intelligent Memory FAQ entry on the issue.
While I'd be happy to see someone get their hands on some 16GB SO-DIMMs and prove otherwise, my limited guess is that 64GB support in the Late 2014 iMac is unlikely.
As for why anyone would need or want 64GB RAM in a desktop, any sort of analytics over about-that-size datasets is the first thing that comes to mind. Perhaps also developing and testing in-memory databases, or cluster technologies with bunches of VMs. The 1TB PCIe SSD is quick, but RAM is still a lot faster. Smoke 'em if you got 'em.