Late 2015 27 iMac 5k RAM spec

Too pricey for me - I'm also not quite that adventurous re. getting double the Apple recommended RAM, especially at that price...... enjoy yours!

Thanks, I'll enjoy it painfully because it hurt buying that ram..lol Any problems i'll send it back.. OWC fully tested the ram and it's operation before releasing to the public. They already have their hands on a new computer and did a whole video on the teardown. If you order your iMac from the apple store with 32gigs of ram its almost the same price as the 2 - 16 gig chips.

http://blog.macsales.com/30510-unboxing-and-teardown-of-the-2015-27-inch-imac-wi th-retina-5k-display

Yeah, OWC has always been my choice for RAM and hard drives and whatever else Mac.

I went back and forth on this. We decided to just get 32GB (4X8GB) from OWC for $264.

$599 was just too much for the same amount of RAM in the 16GB modules. Hopefully the price comes down for the 16GB modules and we can upgrade.

I think 32GB will do just fine for now.

The order for our new iMac was placed last night, can't wait.

At this point, I just find it difficult to see how someone could need 64GB

on a single user machine, unless perhaps allocating a big chunk of it

as RAM disk.

Then again, I guess you could open every single app you would ever intend to ever use

all at once and have them load at boot. Even so.......

Then again, way back when, Bill Gates said no one would ever need more 640KB 😁.

I was in the same boat but went for the latter.

Photoshop and lightroom running side by side. Add a few open plugins and memory is a must or if you are editing video.

Well, I edit a fair amount of videos and I'm doing it with 16 GB RAM - not too bad. However, I don't do it professionally where I'm doing something else while that is going on - if it's a lengthy HD video, I'll walk away and do something else allowing the Mac to focus its entire attention on one task. Gotta remember: even if you have a Mac Pro with the fastest processor and a boatload of RAM, video editing/rendering will take time. A friend of mine worked for one of the major TV stations; they have several running 24/7 editing the reporter's footage as it comes in to ready it for the news and it still takes its time.

Back to the original question: the OWC is listing the exact same 1667 MHz spec

2 x 8GB 1867 MHZ DDR3 SO-DIMM PC3-14900 = $134

http://eshop.macsales.com/item/OWC/1867DDR3S16P/Reviews

BUT, the more common spec is DDR3 1866 (PC3-14900)

For example, this kit on Amazon.com sells for just $88:

Crucial Ballistix Sport 16GB Kit (8GBx2) DDR3 1866 (PC3-14900) 204-Pin SODIMM Memory BLS2K8G3N18AES4 / BLS2C8G3N18AES4

http://www.amazon.com/Crucial-Ballistix-PC3-14900-BLS2K8G3N18AES4-BLS2C8G3N18AES 4/dp/B00DSGLMSM

To me, it looks like it will fit (204 pin SODIMM) , and the decription is:

BLS2K8G3N18AES4 is a 16GB Kit containing (2) 8GB DDR3 modules that operates at speeds up to 1866 MT/s and has a CL10 latency with extended timings of 10-10-10-30. It is Performance and is non-ECC. It conforms to the industry standard SODIMM layout of 204 pins and is compatible with computers that take DDR3 SODIMM memory.

I believe it is just the way they are rounding. The actual spec for PC3-14900 is 1866 2/3 according to Wikipedia: https://en.wikipedia.org/wiki/DDR3_SDRAM

Apple & OWC are rounding up. Most manufacturers are not.

I bought 2 pairs of the Crucial modules that you linked for my new iMac (due to arrive next week).

Please keep us posted if they work or not. Thanks

I Bought two of the new 1867mhz 16GB chips. I wonder if those crucial ballistix modules you mention and purchased in 1866mhz, may be too thick to fit in the iMac. I found these that don't have the ballistix cover just in case.

http://www.amazon.com/gp/aw/d/B00JCRZ6XS/ref=psd_mlt_nbc_B00DSGLMSM_pb

I am also looking at the late 2015 27" iMac. I probably only need 16GB of RAM, but it is actually less expensive to buy the 8GB version from Apple and add 16GB of RAM (2x 8GB) from OWC or Crucial and getting a total of 24GB. Is there a downside to this approach vs. getting the 16GB configuration from Apple?

Absolutely not - I've always purchased my Macs in a standard RAM configuration because of Apple's prices and then added more from OWC later.

Just wanted to say my new Mac shipped! Can't wait...