Can I put 32GB ram on my iMac when max is 16GB?

yoricardo

macrumors member
Original poster
Jun 24, 2010
35
4
I have a 21.5 inch iMac, mid 2011 model. It has been running slow so I decided to buy some extra memory from crucial.com. On their website it says that you can install 32gb of ram on my model and so I went ahead and bought it and have just installed it.

Only after installing it did I have the idea of seeing what it says on the Apple website (yes, backwards thinking, I know) and on the Apple website it says the max for my model is 16gb.

The question is, now I have 32gb, as advised by Crucial, should I just leave 32gb in my machine, or could it damage my Mac?

I appreciate I can call Crucial and they'll sort it out, but I'm interested to know what the implications are of over-speccing the computer.

Thanks!
 

SandboxGeneral

Moderator emeritus
Sep 8, 2010
26,308
9,657
Detroit
Your model is good with 32 GB of RAM and there is nothing to worry about.

MacTracker shows its capable of 32 GB, while Apple, often understates what their computers are capable of.

Screen Shot 2015-10-03 at 7.39.55 AM.png
 
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throAU

macrumors 603
Feb 13, 2012
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Most likely, the Sandy Bridge and later chipset supports 32 GB of RAM.

Apple frequently lists the max RAM capacities as lower than they really are, as I believe they only list what they had on sale as the 'max'.

Back in mid 2011 or so, 8 GB DIMMs (required for 32 GB - x4) were about $800 each (i.e., 32 GB would have cost $3200, you would have been far better off just buying a Mac Pro to get 32 GB with much cheaper 4 GB DIMMs by using more slots that it has available), so that was a very very expensive option that Apple did not offer.
 

yoricardo

macrumors member
Original poster
Jun 24, 2010
35
4
Very interesting, many thanks.

Will I actually get an improved performance over 16GB, however, or is there nothing possible over and above that amount?
 

SandboxGeneral

Moderator emeritus
Sep 8, 2010
26,308
9,657
Detroit
Very interesting, many thanks.

Will I actually get an improved performance over 16GB, however, or is there nothing possible over and above that amount?
I highly doubt the extra RAM will be noticeable for you, unless you're doing many, many, RAM intensive tasks at the same time.

The slow down you're experiencing is probably due to the hard drive in there. If you upgrade to an SSD, that's when you will see an improvement by orders of magnitude.
 

throAU

macrumors 603
Feb 13, 2012
6,382
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Perth, Western Australia
Very interesting, many thanks.

Will I actually get an improved performance over 16GB, however, or is there nothing possible over and above that amount?
Depends what you're doing. More RAM is a case of diminishing returns unless you are running something that needs it.

If you're just doing regular "Stuff" then probably not. If you're running an SSD then less likely.

But if you are working with large video files, multiple large images in photoshop, other operating systems in virtual machines, etc. then more RAM will be useful.

You can perhaps check out the memory pressure graph in activity monitor and see how bad it is when you have a typical "large" workload running.

For most people 16 GB is plenty (hell, 8 GB is plenty for most, especially with an SSD), but you may be different. I did notice a general speed up on my 15" MBP going from 8 GB to 16 GB with a hard drive, but it was nowhere near the difference between 4 GB and 8 GB for general use. It was like 10% of the improvement if that when doing basic stuff, and that was due to hard disk cache. SSD in the box, and that improvement won't be significant.

Going from 16 GB to 32 GB for general non-ram-intensive stuff will be even less noticeable. If you've got 16 GB and a hard drive i would suggest your best bang for buck upgrade would be an SSD.
 
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dogslobber

macrumors 68040
Oct 19, 2014
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Apple Campus, Cupertino CA
I have a 21.5 inch iMac, mid 2011 model. It has been running slow so I decided to buy some extra memory from crucial.com. On their website it says that you can install 32gb of ram on my model and so I went ahead and bought it and have just installed it.

Only after installing it did I have the idea of seeing what it says on the Apple website (yes, backwards thinking, I know) and on the Apple website it says the max for my model is 16gb.

The question is, now I have 32gb, as advised by Crucial, should I just leave 32gb in my machine, or could it damage my Mac?

I appreciate I can call Crucial and they'll sort it out, but I'm interested to know what the implications are of over-speccing the computer.

Thanks!
This type of machine runs great with 32gb of ram. In fact, it's the last 21.5" iMac to be able to do that as 2012 onwards only had two dimm slots.
 

Sirmausalot

macrumors 65816
Sep 1, 2007
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275
On trick to get great performance out of an older Mac is to upgrade to an SSD-- and the trick part is to use an external SSD and use it as a boot drive for the OS and all of your programs. That way you don't have to open the machine up. A much, much better investment than more RAM after 16GB...
 
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fastlanephil

macrumors 65816
Nov 17, 2007
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Very interesting, many thanks.

Will I actually get an improved performance over 16GB, however, or is there nothing possible over and above that amount?
You can run Apple's Activity Monitor(it's in the utilities folder) to see how much memory you're using and how much headroom you still have. It also checks CPU and disk use.
 

rkaufmann87

macrumors 68000
Dec 17, 2009
1,760
38
Folsom, CA
I have a 21.5 inch iMac, mid 2011 model. It has been running slow so I decided to buy some extra memory from crucial.com. On their website it says that you can install 32gb of ram on my model and so I went ahead and bought it and have just installed it.

Only after installing it did I have the idea of seeing what it says on the Apple website (yes, backwards thinking, I know) and on the Apple website it says the max for my model is 16gb.

The question is, now I have 32gb, as advised by Crucial, should I just leave 32gb in my machine, or could it damage my Mac?

I appreciate I can call Crucial and they'll sort it out, but I'm interested to know what the implications are of over-speccing the computer.

Thanks!
32 will be fine but totally unnecessary .
 

throAU

macrumors 603
Feb 13, 2012
6,382
3,864
Perth, Western Australia
You can run Apple's Activity Monitor(it's in the utilities folder) to see how much memory you're using and how much headroom you still have. It also checks CPU and disk use.
Yeah the kinda fuzzy thing is that with a spinning disk, more RAM will help with caching a fair bit, but much more than 16 GB the benefit of that becomes more and more dubious... a complete base install of OS X is about 10 gb from memory, there's only so much more caching can do.

I'd say if you're running 16 GB and a spinning disk you'd probably want to be upgrading to SSD as a priority. RAM will of course help by caching, but the stuff has to get into memory in the first place from the disk somehow and that part will still be slow...

Again, not to say 32 GB won't help... just probably not as much as an SSD. If that makes sense.
 
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yoricardo

macrumors member
Original poster
Jun 24, 2010
35
4
Very interesting suggestion re upgrading to an SSD. Which one would you recommend so I can work out a cost/benefit comparison?
 

randalf72

macrumors member
Apr 25, 2014
47
13
I've had good experiences with the Samsung 840Pro and the new 850 seems to be a whole order of magnitude cheaper with very similar performance/warranty specs to the 840Pro.

UK Prices, which I accept may give a false idea (due to us getting ripped off by everyone when it comes down to computer gear) are roughly £115 for the 500gb version inclusive of all taxes, so maybe around $150 in the US?
 

tomilchik

macrumors newbie
Feb 4, 2016
2
0
32 will be fine but totally unnecessary .
It really depends. I just upgraded memory on my iMac 27" mid-2011: added two 4GB units to the existing 2x2GB to the total of 12GB.
Immediate effect: it seems that Safari and Mail come up faster. But that's the perceived, not measured.
Now - concrete #'s:
with the following apps running - Safari (8 tabs), Mail, Activity Monitor, LogicPro X, Photos - I see these figures:
- Memory Used: 6.40GB
- Cache: 4.65 GB (it is my understanding that Cache is not *part* of Memory Used, but *in addition to*).
- Swap Used: 0

Altogether: iMac happily sucked into memory close to 11GB of stuff => much less disk I/O (I wish I had kept track of Disk I/O before I installed the upgrade). This to me is another benefit of more RAM: not only things come up and run faster - disk works less, and perhaps will live longer.

I didn't want to risk throwing too much money away based on semi-official info that my iMac can take 4x8GB=32GB. But I am very likely to replace my original 2x2GB=4GB with 2x4=8GB to the total of 16GB. And regret not upgrading to 32GB if/when someone comes up with convincing confirmation of 1)successfully upgrading, and 2)seeing iMac actually using all 32 (or at least beyond 16)
 

Samuelsan2001

macrumors 604
Oct 24, 2013
7,694
2,121
It really depends. I just upgraded memory on my iMac 27" mid-2011: added two 4GB units to the existing 2x2GB to the total of 12GB.
Immediate effect: it seems that Safari and Mail come up faster. But that's the perceived, not measured.
Now - concrete #'s:
with the following apps running - Safari (8 tabs), Mail, Activity Monitor, LogicPro X, Photos - I see these figures:
- Memory Used: 6.40GB
- Cache: 4.65 GB (it is my understanding that Cache is not *part* of Memory Used, but *in addition to*).
- Swap Used: 0

Altogether: iMac happily sucked into memory close to 11GB of stuff => much less disk I/O (I wish I had kept track of Disk I/O before I installed the upgrade). This to me is another benefit of more RAM: not only things come up and run faster - disk works less, and perhaps will live longer.

I didn't want to risk throwing too much money away based on semi-official info that my iMac can take 4x8GB=32GB. But I am very likely to replace my original 2x2GB=4GB with 2x4=8GB to the total of 16GB. And regret not upgrading to 32GB if/when someone comes up with convincing confirmation of 1)successfully upgrading, and 2)seeing iMac actually using all 32 (or at least beyond 16)
You would still be better off performance wise with a SSD over RAM......
 
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tomilchik

macrumors newbie
Feb 4, 2016
2
0
You would still be better off performance wise with a SSD over RAM......
If you mean "upgrading HD to SSD" vs "upgrading RAM to bigger" - then yes, agree.

Money-wise: SSD comes out much cheaper per 1GB - about $0.5/GB (1TB for $500); RAM - mine cost me ~$7/GB ($56 for 8GB). One-time cost with SSD will be higher, and upgrade/installation is more complicated - not everybody will have guts to do it at home, and a comp shop will charge whatever they charge (I saw someone mentioning $100).

So in the end it boils down to how much people want to spend on what kind of performance improvement. $60 for somewhat noticeable improvement; or $200-500 for very noticeable.
 

off_piste

macrumors 6502a
Oct 25, 2015
763
480
I put 32 gb of ram in my mid 2011 iMac. The system recognizes it even though it claims a max of 16. Doubt it was necessary but that's never stopped me from pointlessly upgrading in the past.
 

DaCraftyFox

macrumors newbie
May 10, 2017
1
0
I put 32 gb of ram in my mid 2011 iMac. The system recognizes it even though it claims a max of 16. Doubt it was necessary but that's never stopped me from pointlessly upgrading in the past.
Hello all!

I've upgraded my 27 iMac mid2010 from 8g to 32gb, mainly because I work with some huge files in photoshop from time to time.

The thing is, also from time to time, I get multiple crashes... and then it reboots to this:



I can insert here one or the reports that the system presents me after the reboot. It really is annoying once it can crash and reboot every 2 min... for one day, or 2 or 5... And then, it keeps running perfectly for months.

Any ideas?
 

Richdmoore

macrumors 68000
Jul 24, 2007
1,811
270
Troutdale, OR
I have a 21.5 inch iMac, mid 2011 model. It has been running slow so I decided to buy some extra memory from crucial.com. On their website it says that you can install 32gb of ram on my model and so I went ahead and bought it and have just installed it.

Only after installing it did I have the idea of seeing what it says on the Apple website (yes, backwards thinking, I know) and on the Apple website it says the max for my model is 16gb.

The question is, now I have 32gb, as advised by Crucial, should I just leave 32gb in my machine, or could it damage my Mac?

I appreciate I can call Crucial and they'll sort it out, but I'm interested to know what the implications are of over-speccing the computer.

Thanks!
I have the exact same Mac, and am running 32g without issues.
 

redheeler

macrumors 604
Oct 17, 2014
7,659
7,491
Hello all!

I've upgraded my 27 iMac mid2010 from 8g to 32gb, mainly because I work with some huge files in photoshop from time to time.

The thing is, also from time to time, I get multiple crashes... and then it reboots to this:



I can insert here one or the reports that the system presents me after the reboot. It really is annoying once it can crash and reboot every 2 min... for one day, or 2 or 5... And then, it keeps running perfectly for months.

Any ideas?
Try running Apple Hardware Test to see if your RAM passes. I was having crashes & kernel panics on my 5K iMac like you described, and it turned out the RAM failed the test. Returned/replaced the defective RAM and it now works just fine.
 
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cynics

macrumors G4
Jan 8, 2012
11,554
1,874
I found if you have a HDD if you stuff a lot of RAM into it and leave it on all the time it's stays fairly quick. I don't notice any slow downs or beach balls.

However after a fresh reboot it's a turd. An SSD will make a bigger difference in everyday task then any other upgrade (unless you are doing very specific task like after effects).
 
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