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T Coma

macrumors 6502a
Dec 3, 2015
659
1,249
Flyover Country, USA
Sigh, whatever guys.
You slap in your extra RAM and be thankful you've saved a few bucks and I'll replace all the RAM and be happy I was getting a stable machine, there you go sorted....

Count me as another one of the "lucky chaps" with mixed brands and sizes of RAM in my iMac. Now they've only been installed and running smoothly for ~6 years, so I suppose it could eventually cause a problem and get unstable. :rolleyes:
 

cynics

macrumors G4
Jan 8, 2012
11,959
2,156
Count me as another one of the "lucky chaps" with mixed brands and sizes of RAM in my iMac. Now they've only been installed and running smoothly for ~6 years, so I suppose it could eventually cause a problem and get unstable. :rolleyes:

I’m over 4 years now! Sooooo lucky....some people..

Like many PC components the RAM capacity and capabilities needs to be compatible with the CPU. RAM is where the CPU goes looking for data if its not found in its own cache. There are reasons system RAM specs may vary from the CPU RAM specs but they are often financial, heat related, board speeds, etc...

Mac RAM isn’t anything special though. Consider this, if a Mac is using Hynix RAM and you get the same spec Hynix ram would that be a problem?

Since RAM is so dependent on the CPU Apple couldn't get to strict with particulars nor would it make sense for them too.

Admittedly there are considerations. Like @SaSaSushi points out some RAM has specific techniques they use to further enhance performance. But 'like for like' there is no benefit in replacing the OEM ram as long as you are using RAM that meets the requirements for the iMac.

EDIT: Grammar sheesh...
 
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Chancha

macrumors 68020
Mar 19, 2014
2,300
2,125
Would that be Kingston HyperX? That is known to be incompatible with Apple's stock RAM because it is actually overclocked and not standard PC4-19200.

It is covered in detail in the thread I linked to in my previous post.
Kingston does have RAM with matching specs for the iMac, I got 2 sticks of 16GB, working together with Apple's stock 4+4GB for a total of 40GB, running for months no problem.

The part number is KCP424SD8/16 for your reference.

I have no idea why so many people bought the HyperX instead, it quite obviously has mismatching specs as what compatible RAM Apple listed.
 

nambuccaheadsau

macrumors 68020
Oct 19, 2007
2,024
510
Blue Mountains NSW Australia
Never touch anything Kingston - memory, SSDs etc.

Stick with Crucial and you will have no problems. Have upgraded memory from the Bondi Blue 233Mhz iMac, through towers, Mac Pros, late model iMacs and laptops and have never had a module problem. Avoid PC shop and eBay memory.
 

csurfr

macrumors 68020
Dec 7, 2016
2,310
1,748
Seattle, WA
if you have a 2017 5k iMac your max amount of ram is dependent on which one you buy. The 3.4ghz i5 only (according to Apple) supports 32gb of RAM. The 3.5ghz i5 and up support 64gb of RAM. Not sure why the 3.4ghz has a limit of 32gb.
 

Brian Y

macrumors 68040
Oct 21, 2012
3,776
1,064
if you have a 2017 5k iMac your max amount of ram is dependent on which one you buy. The 3.4ghz i5 only (according to Apple) supports 32gb of RAM. The 3.5ghz i5 and up support 64gb of RAM. Not sure why the 3.4ghz has a limit of 32gb.

This is purely a sales limitation. There’s no per-model differences in ram capacity.

I have crucial in mine - works like a charm.
 
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Bluesman67

macrumors newbie
Feb 10, 2018
1
0
This is obviously not true. The people at Applecare do not get advanced information about the products. They don't find out until we find out.

What is true is that you cannot both use apples original 8 GB of RAM and simultaneously upgrade the machine to 64 GB of RAM. You have to take their memory out and throw it away (or give it away, or sell it for a couple of bucks) in order to install four of the 16 GB memory sticks.

There are people who have iMac A1312 Mid 2011 running 32GB Ram.
 

AlaskaMoose

macrumors 68040
Apr 26, 2008
3,586
13,429
Alaska
How difficult is it to remove and replace the RAM sticks on the 2017 21" iMac? I have a couple of 2010 iMacs and replacing the RAM is very easy after removing the small panel at the bottom edge of the iMac.

I will buy a new 21.5" iMac with the i7 processor and 32GB RAM. It would cost me around $2,300 by the time I configure it the way I want, but maybe I should order it with 8GB RAM, and buy Crucial or "macsales.com" RAM to keep the cost a little lower?

P.S. Just watched the RAM installation instructions, and it can be difficult to remove and replace the RAM sticks. The screen and a few of the internal components have to be removed in order to reach the RAM sticks. But while buying the 32GB RAM from Crucial or OMC cost around $300.00, buying from Apple would cost $600.00. I have to think about this carefully and decide if $300.00 plus a couple of hours labor is worth the trouble. Also, I hear that the i7 processors increases cooling fans noise.
 
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Alark84

macrumors newbie
Feb 11, 2018
1
0
So I own an iMac 27” late 2013 running 16GB of RAM and I guess the most I can run on this model is 32GB with 8GB in each slot? Is this correct? I tried to find out on the Apple website but that information was left blank. My InDesign keeps saying out of memory when I’m working on larger projects and I know I need more memory, but how much can my model actually hold? And Crucial is the best to buy?
 

AlaskaMoose

macrumors 68040
Apr 26, 2008
3,586
13,429
Alaska
So I own an iMac 27” late 2013 running 16GB of RAM and I guess the most I can run on this model is 32GB with 8GB in each slot? Is this correct? I tried to find out on the Apple website but that information was left blank. My InDesign keeps saying out of memory when I’m working on larger projects and I know I need more memory, but how much can my model actually hold? And Crucial is the best to buy?

Crucial and "macsales.com" are good places to buy. Also, at "macsales.com" follow their instructions on how to find your iMac model's ID (go to Memory, and choose the link for the iMac RAM). You should also know some things ahead of time. Choose "About This Mac" under the Apple menu, then Overview. The year your computer was made, including early/late 2013 will be shown in there. Once you have that information, go to "macsales" and open the "Memory" link for the computer you have. That will tell you which RAM kits to buy.
 

MacGizmo

macrumors 68040
Apr 27, 2003
3,211
2,513
Arizona
How difficult is it to remove and replace the RAM sticks on the 2017 21" iMac?
Technically speaking it can be done... but risking a $2K Mac to save $200-$300 seems silly to me. As far as the fan noise on an i7: I have an i7 and the only time I hear the fan ever come on is when a rogue website has some bad Flash graphics displaying.
[doublepost=1518436352][/doublepost]
Sigh, whatever guys.
You slap in your extra RAM and be thankful you've saved a few bucks and I'll replace all the RAM and be happy I was getting a stable machine, there you go sorted....
Yeah, I've been mixing brands for decades on dozens of Macs. No issues at all. When the experts recommend matched pairs, they don't mean the BRAND of RAM, they mean the speed/size of the RAM.

And for the record, Apple doesn't use "cheap" RAM and charge a lot for it. They use nearly the highest quality RAM available... and charge A LOT + $200 for it ;)
 
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colodane

macrumors 65816
Nov 11, 2012
1,047
483
Colorado
I would not recommend adding RAM to a 2017 21.5 inch iMac. In addition to being difficult, it will void your warranty.

Suggest taking a fresh look and considering getting a 27 inch instead. i5 processor and SSD. Then add more RAM yourself.
You will end up with a superior machine for about the same $$ and a lot less aggravation. .
 
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AlaskaMoose

macrumors 68040
Apr 26, 2008
3,586
13,429
Alaska
Technically speaking it can be done... but risking a $2K Mac to save $200-$300 seems silly to me. As far as the fan noise on an i7: I have an i7 and the only time I hear the fan ever come on is when a rogue website has some bad Flash graphics displaying.
[doublepost=1518436352][/doublepost]
Yeah, I've been mixing brands for decades on dozens of Macs. No issues at all. When the experts recommend matched pairs, they don't mean the BRAND of RAM, they mean the speed/size of the RAM.

And for the record, Apple doesn't use "cheap" RAM and charge a lot for it. They use nearly the highest quality RAM available... and charge A LOT + $200 for it ;)

I appreciate your response, and agree with you that it makes no sense to crack open a brand new iMac to replace RAM modules. Yes, I would do it after the warranty has expired, but not before.
[doublepost=1518497904][/doublepost]
I would not recommend adding RAM to a 2017 21.5 inch iMac. In addition to being difficult, it will void your warranty.

Suggest taking a fresh look and considering getting a 27 inch instead. i5 processor and SSD. Then add more RAM yourself.
You will end up with a superior machine for about the same $$ and a lot less aggravation. .

Is the RAM easier to replace on the 27" 2017 iMac? Never mind my question. I just watched a video on how to replace the RAM modules own the 2017 27" iMac. and it's just as easy, if not easier to do than my 2011 21.5" iMac.
 
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haruhiko

macrumors 604
Sep 29, 2009
6,686
6,239
Kingston does have RAM with matching specs for the iMac, I got 2 sticks of 16GB, working together with Apple's stock 4+4GB for a total of 40GB, running for months no problem.

The part number is KCP424SD8/16 for your reference.

I have no idea why so many people bought the HyperX instead, it quite obviously has mismatching specs as what compatible RAM Apple listed.
Because they labelled them as iMac 2017 compatible in the package in my country, of course disregarding the incompatibility with the stock RAMs.
 

Chancha

macrumors 68020
Mar 19, 2014
2,300
2,125
Because they labelled them as iMac 2017 compatible in the package in my country, of course disregarding the incompatibility with the stock RAMs.
Sorry to hear that.

They technically aren't being wrong / dishonest there, the RAMs are indeed compatible to the iMac, with the presumption of using just those RAMs. The chipset that the iMac use have a range of speed and latency of RAMs that can be used and Apple didn't put any extra limits, coupled with the fact that the hatch door is user accessible, I would consider it a case of giving users freedom but also offloading the burden to them.
 

haruhiko

macrumors 604
Sep 29, 2009
6,686
6,239
Sorry to hear that.

They technically aren't being wrong / dishonest there, the RAMs are indeed compatible to the iMac, with the presumption of using just those RAMs. The chipset that the iMac use have a range of speed and latency of RAMs that can be used and Apple didn't put any extra limits, coupled with the fact that the hatch door is user accessible, I would consider it a case of giving users freedom but also offloading the burden to them.
I ended up selling the hyper X at a loss and bought another pair of RAM sticks that are actually compatible with the stock RAM. Lesson learnt.
 

theluggage

macrumors G3
Jul 29, 2011
8,008
8,441
Is the RAM easier to replace on the 27" 2017 iMac? Never mind my question.

Its completely different: on a 21.5" you have to follow DIY instructions on somewhere like iFixit: cut the double-sided adhesive holding the screen on and partly disassemble the innards to get at the RAM slots, then you'll need a replacement set of adhesive tapes to put the screen back on. Not for the faint hearted - you might consider it to extend the life of an out-of-warranty iMac, but not on a brand-new one.

On the 27" 5k the RAM is officially user-upgradeable - you can find Apple's own instructions on their support site - just push a little button hidden by the power connector, a little door in the back of the case pops open and exposes just the RAM sockets and a little lever to release them. On an 8GB iMac there are two empty sockets - sweet spot is probably to get the 8GB model and add 2x8GB sticks to get 24GB. Crucial.com have a tool that points you to the correct RAM, and its the same Micron RAM that Apple use. You get a 24GB Mac for less than Apple's price for a 16GB one.

Only gotcha is that Crucial recommend a different, slightly slower RAM for the base i5 iMac 5k, as opposed to the faster i5 and i7 models - but their guide tool will tell you that.

Don't know why people are getting bogged down with "super-mega-X-ultra with go-faster stripes and fancy heatsink designed to look good in your illuminated plexiglass PC gaming rig and impress you friends by running Crysis at 150fps to their pathetic 149fps RAM"...
 

Brian Y

macrumors 68040
Oct 21, 2012
3,776
1,064
In theory, there should be no issue running different brands of RAM as long as the latencies match - mismatched latencies will give you issues.

Try to get the same speed or faster though - it will down clock to the lowest common denominator.
 

AlaskaMoose

macrumors 68040
Apr 26, 2008
3,586
13,429
Alaska
Its completely different: on a 21.5" you have to follow DIY instructions on somewhere like iFixit: cut the double-sided adhesive holding the screen on and partly disassemble the innards to get at the RAM slots, then you'll need a replacement set of adhesive tapes to put the screen back on. Not for the faint hearted - you might consider it to extend the life of an out-of-warranty iMac, but not on a brand-new one.

On the 27" 5k the RAM is officially user-upgradeable - you can find Apple's own instructions on their support site - just push a little button hidden by the power connector, a little door in the back of the case pops open and exposes just the RAM sockets and a little lever to release them. On an 8GB iMac there are two empty sockets - sweet spot is probably to get the 8GB model and add 2x8GB sticks to get 24GB. Crucial.com have a tool that points you to the correct RAM, and its the same Micron RAM that Apple use. You get a 24GB Mac for less than Apple's price for a 16GB one.

Only gotcha is that Crucial recommend a different, slightly slower RAM for the base i5 iMac 5k, as opposed to the faster i5 and i7 models - but their guide tool will tell you that.

Don't know why people are getting bogged down with "super-mega-X-ultra with go-faster stripes and fancy heatsink designed to look good in your illuminated plexiglass PC gaming rig and impress you friends by running Crysis at 150fps to their pathetic 149fps RAM"...

Thanks for all the advice from several of you in this thread. I have decided that I will buy a 27" iMac, but not right away. I will wait for Apple to release the 2018/19 27" iMac, then buy one. However, I will buy it with the standard 1 or 2TB hard drive instead of SSD, then replace it with a 1TB SSD from "macsales.com" (or Crucial) once the warranty is over. But I will order it with an 8GB RAM stick, and right after replace it with a 64GB RAM kit from "macsales."

I have been using a late 2009, 21.5" iMac with the following specifications:
-OS Yosemite version 10.10.5
-3.33GHz Intel Core Duo
-16GB RAM
-Graphics: ATI Redeon HD 4670 256GB
-1TB SATA hard drive

I have edited thousands of my photographs using this iMac, and while not very fast, it has done quite well for me using a standalone CS6, and some of the OneOne software, plus my favorite, NIK's software bundle. What I will do while I wait for the newer iMac is to replace the hard drive with a 2TB SSD.

I also have a 13 MacBook Pro that I have been using daily since 2011. I just use it at work for mundane tasks like checking or writing emails, writing documents using Nisus Writer Pro 2 (writing in different languages), Pages, and so on.

Specs:
-OS High Sierra
-13" MacBook Pro (early 2011)
-2.3GHz Intel Core i5
-16GB RAM
-Graphics: Intel HD 3000 512MB
-Hard drive: 320GB SATA

On this one I will replace the internal hard drive with a 500GB "machales.com" SSD for $195.00. The kit comes with the drive, an enclosure for it, the screwdrivers and other hardware needed to open the MacBook. I can use the enclosure with another hard drive or SSD. I can keep on using it as it is not, but the SSD kit is not a bad deal.
 
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mbosse

macrumors 6502a
Apr 29, 2015
629
199
Vienna, Austria
Thanks for all the advice from several of you in this thread. I have decided that I will buy a 27" iMac, but not right away. I will wait for Apple to release the 2018/19 27" iMac, then buy one. However, I will buy it with the standard 1 or 2TB hard drive instead of SSD, then replace it with a 1TB SSD from "macsales.com" (or Crucial) once the warranty is over. But I will order it with an 8GB RAM stick, and right after replace it with a 64GB RAM kit from "macsales."

I have been using a late 2009, 21.5" iMac with the following specifications:
-OS Yosemite version 10.10.5
-3.33GHz Intel Core Duo
-16GB RAM
-Graphics: ATI Redeon HD 4670 256GB
-1TB SATA hard drive

I have edited thousands of my photographs using this iMac, and while not very fast, it has done quite well for me using a standalone CS6, and some of the OneOne software, plus my favorite, NIK's software bundle. What I will do while I wait for the newer iMac is to replace the hard drive with a 2TB SSD.

I also have a 13 MacBook Pro that I have been using daily since 2011. I just use it at work for mundane tasks like checking or writing emails, writing documents using Nisus Writer Pro 2 (writing in different languages), Pages, and so on.

Specs:
-OS High Sierra
-13" MacBook Pro (early 2011)
-2.3GHz Intel Core i5
-16GB RAM
-Graphics: Intel HD 3000 512MB
-Hard drive: 320GB SATA

On this one I will replace the internal hard drive with a 500GB "machales.com" SSD for $195.00. The kit comes with the drive, an enclosure for it, the screwdrivers and other hardware needed to open the MacBook. I can use the enclosure with another hard drive or SSD. I can keep on using it as it is not, but the SSD kit is not a bad deal.
Do yourself a favour and do not use OWC/Macsales SSDs. RAM is ok as well as their DIY SSD install kits (caveat again, not the SSDs themselves), but their SSDs are basically tinkerer stuff. You may check several threads here. Crucial is very good as is Samsung, Intel or Sandisk.

If you are to open it, you might as well find second hand original Apple SSDs at acceptable prices.

Good luck,Magnus
 
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theluggage

macrumors G3
Jul 29, 2011
8,008
8,441
I will wait for Apple to release the 2018/19 27" iMac, then buy one. However, I will buy it with the standard 1 or 2TB hard drive instead of SSD, then replace it with a 1TB SSD from "macsales.com"

Whoa! There is no guarantee whatsoever that any of this advice will apply to the hypothetical 2018/9 iMac. The current 27”s easily upgraded RAM is already an aberration in Apple’s range and it’s probably time for the non-SSD options to disappear, too. Nobody knows if/when the new models will arrive or how different they will be.

By all means wait if you don’t need a new system urgently - the new intel processors with more cores could be worth waiting for - but don’t expect your plans to be relevant to any new models.

Also, there’s already no HD-only model and friends don’t let friends buy the 1TB fusion drive model. It has a pitifully small SSD component and many people here have reported lacklustre performance - at the very least get the 2TB fusion, which has a bigger SSD but, really, there’s no place for spinning rust in an iMac.
 
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