Optimal Memory (RAM) layout for mid 2017 iMac 27‑inch with Retina 5K display?

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Level 2

159 points

Optimal Memory (RAM) layout for mid 2017 iMac 27‑inch with Retina 5K display?

The iMac comes with 8GB 2400MHz DDR4 (I understand they are 2x4GB modules).

1. Should memory modules be added in pairs? Why?

2. If 2x16GB modules with the same specifications from Kingston (3.2 times cheaper!!!) are added, how should all modules show in the rear of the iMac slots? (top to bottom with iMac on upright position):

4 - 4 - 16 -16?

4 - 16 - 4 -16?

4 - 16 - 16 -4?

16 - 4 - 4 - 16?

16 - 4 - 16 - 4?

16 - 16 - 4 - 4?

Does it affect performance? Why?

3. How should they show in "Apple - About This Mac - System Report - Hardware - Memory - Memory Slot"? Like this? (or whatever):

BANK 0/DIMM0 4 GB

BANK 0/DIMM1 4 GB

BANK 1/DIMM0 16 GB

BANK 1/DIMM1 16 GB

Thanks.

Posted on Jul 15, 2017 12:28 PM

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Answer 1

ApMaX Author

Level 2

159 points

Jul 15, 2017 2:15 PM in response to Csound1

Could someone please answer my questions above. Thanks.

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Answer 2

SeaPapp

Level 7

26,492 points

Jul 15, 2017 12:38 PM in response to ApMaX

You should avoid Kingston. Macs are picky about the correct spec ram and kingston is one of the brands that considers close to be good enough. Quality exact soec ram can be purchased from either OWC or Crucial at competitive prices. As far as layout, don over think it and put the new modules in the empty slots.

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Answer 3

ApMaX Author

Level 2

159 points

Jul 15, 2017 12:45 PM in response to SeaPapp

Thanks for the quick reply. As far as I know, Kingston is the best brand for Macs. At least, that used to be like that with thousands of Mac updated by my local reseller over many years. Is Crucial better now?

On the other hand, I will appreciate answers to my questions above (to learn). Thanks again.

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Answer 4

ApMaX Author

Level 2

159 points

Jul 15, 2017 1:58 PM in response to Csound1

I do not mean "value RAM" (whatever that is). I mean the specific RAM shown when selecting at

http://www.kingston.com/us/memory/desktop-notebook

the Mac model. In this case:

System Specific Memory for Apple iMac Retina 5K, 27-inch (2017)

From the world’s independent memory leader. Each module is designed, manufactured, tested and tailored to maximize the performance of a specific brand name computer system.

16GB Module - DDR4 2400MHz

Part Number: KCP424SD8/16

Specs: DDR4 , 2400MHz , Non-ECC , CL17 , X8 , 1.2V , Unbuffered , SODIMM , 260-pin

http://www.kingston.com/us/memory/search?DeviceType=2&Mfr=APP&Line=iMac&Model=96 522

Actually, it is more expensive than the one at Crucial

http://www.crucial.com/usa/en/memory-info?cm_re=top-nav-_-flyout-memory-_-us-mem ory

Is then Crucial better than the Kingston above?

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Answer 5

babowa

Level 9

78,556 points

Jul 15, 2017 2:54 PM in response to ApMaX

On older iMac models, the RAM slots were two rows with two next to one another in each row. That is how you paired them (the same RAM in the same row).

On new models, the slots are arranged vertically. The OEM RAM is - as far as I know - arranged in slot 1 and 3 (from the top or bottom depending on which way the Mac is facing you. If you are just getting 2 modules, they should simply go into the empty slots (2 and 4 in my example) which will make them show up as paired next to one another in the System info. Why it does that I do not know - only Apple would. Their diagram is confusing at best.

As for Kingston, it is not and never has been the best brand for Mac - I've been dealing with Macs since 1995. Of course they're cheaper. Macs are extremely finicky about their RAM. You will have to accept longtime users' opinions on the matter - if you still wish to buy Kingston, go ahead. It is your Mac. Hopefully, they have a lifetime warranty.

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Answer 6

SeaPapp

Level 7

26,492 points

Jul 15, 2017 7:24 PM in response to ApMaX

Is then Crucial better than the Kingston above?

Personally I wouldn't use Kingston ram to prop open a door. My first choice is OWC because of their outstanding support and then Crucial. Both IMO are better than Kingston.

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Answer 7

Csound1

Level 9

60,063 points

Jul 15, 2017 12:50 PM in response to ApMaX

You know wrong, Kingston, especially the cheap 'value ram' is one of the worst choices of RAM for a Mac.

Crucial and OWC are the best choices.

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Answer 8

Csound1

Level 9

60,063 points

Jul 15, 2017 2:04 PM in response to ApMaX

Look it is your money, buy what ever you want to with it.

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