iMac 24 Maximum Memory??

I have a 24-Inch iMac, mid 2007 model - and I am trying to upgrade the memory from 2Gb to 4GB.


According to everything I have read, the maximum memory that this system can handle is 4GB. I bought 2 new Kingston memory modules and installed them into the system, and it would not boot.


I tried some tests.. I installed one old 1Gb module with one new 2GB module, and it booted fine. I then swapped the 2GB module with the other, and again, it booted fine - indicating to me that the memory is good. When checking the sys info, it indicated 3GB was installed (in both cases).


However, whenever I put in both new 2GB modules, it fails to boot - nothing happens.. black screen, and internal fans running.


Does this system really support 4GB? It is running an Intel processor, and from my PC days, I believe the maximum memory that an Intel PC can handle is 3 GB in 32-bit mode.. I think the limitations are removed when running a 64-bit processor. (not sure if my iMac is running 32 or 64 bit, but I suspect it is 32). So, I am really wondering if the max I can use is only 3GB.


Would appreciate your comments and / or suggestions.. thanks!!


Paul

iMac, Mac OS X (10.7.3)

Posted on Mar 9, 2012 12:05 PM

Reply
14 replies

Mar 9, 2012 12:13 PM in response to iMac39

According to OWC, it can actually handle up to 6Gb - http://eshop.macsales.com/shop/apple/memory/iMac


The core 2 duo processor in your iMac is a 64-bit cpu. Even the 32-bit kernel version of OS X has long supported 64-bit memory addressing for apps (that is, the 32-bit kernel is limited to 4Gb useable space itself, but the system can allow 64-bit memory space for apps to run in).


Was this kingston RAM specifically listed as Apple compatible? Macs can be very demanding of having just the right CAS latency and other specs correct.


It's kingston, so you should be able to return it if it does not work (they've always had a good lifetime warranty). OWC empirically tests the setups they support on their web site, so if they say 6Gb will work and you buy their RAM they will fully support you if it has any issues.


My MBP originally was said to only run 4Gb max. but it's been happily running 8Gb for quite awhile now.

Mar 9, 2012 12:32 PM in response to Michael Black

Michael, thanks for the reply


The memory I bought was from Tirger Direct, and is listed as 2GB, DDR2 800 MHz, PC2-6400 - said to be compatible with 800MHz (PC2-6400), 667 MHz (PC2-5300), and 553 MHz (PC2-4200).


The actual P/N on the module is KVR800D2S0/2GR - do you know if these modules are copmatible with this iMac?


If they are not, why does only one work and not both together?


Paul

Mar 9, 2012 3:07 PM in response to iMac39

The part number you listed starts with KVR which indicates Kingston Value Ram; there have been several reports with problems with that type of RAM. As Michael said, iMacs are very particular about RAM and it is best to avoid all "value" RAM. I'd return that and buy it at the link Michael provided.


Also, could you confirm that your model ID is 7,1 please.

Mar 9, 2012 3:28 PM in response to iMac39

iMac39,


In addition to babowa's wise comments you purchased the wrong specification RAM. The late 2007 iMac's use PC5300 DDR2 667MHz 200 Pin. I would STRONGLY recommend returning the RAM and repurchasing from OWC. The URL to 6GB of RAM is:


http://eshop.macsales.com/item/Other%20World%20Computing/5300DDR2S6GP/


the 4GB kit is:


http://eshop.macsales.com/item/Other%20World%20Computing/5300DDR2S4GB/


Good luck!

Mar 9, 2012 3:37 PM in response to babowa

babowa wrote:


I hadn't touched on the RAM specs issue because I want to make sure it's a 7,1; sometimes people use the date purchased as an indicator - for instance, a lot of people say they have a late 2010 or 2011: there is no such thing; they were called mid 2010 and 2011.

Yup I know, you took the cautious route I took the devil may care route. 🙂

Mar 9, 2012 4:35 PM in response to iMac39

As already mentioned, the Kingston value line can be problematic with Apple machines - kind of hit or miss. Apple's systems are just generally not forgiving of much of anything out of spec in terms of latency or timing in modules.


If you go to http://www.kingston.com/us/memory/system_specific/desktop_notebook and look up your system, you will not find them suggesting any of their value line modules - they will list KTA- part numbers which are their higher end modules that they actually guarantee meet or exceed Apple's specs.


I would return it. As I said, you should have no problem as Kingston has always been excellent about their lifetime warranty, and just tell them it is not working in your iMac. The only companies I will buy RAM from are OWC, Crucial or Kingston (and always direct from those latter two's web sites) as they really do stand by their products and guarantees (Crucial and Kingston actually make RAM chips too, OWC contracts for theirs but use quality modules that they themselves test to work, usually using actial RAM chips from Crucial, Kingston or often Samsung, wich is a common OEM RAM supplier in Apple machines).


For the price, I'd go for the 6Gb from OWC - you take a minor performance hit by having to use a mixed set (2Gb and a 4Gb) but it is hardly anything you would even be able to notice in normal daily use.

Mar 9, 2012 7:15 PM in response to Michael Black

Ok, thanks for the replies..


Babowa mentioned:

Also, could you confirm that your model ID is 7,1 please.

Yes, this is a model 7,1


And Michael, thanks for the information.. I will order the correct memory.. I just needed it in a hurry for a project that had to be completed this weekend, and was finding that Aperture was running quite slowly, so thought I would bump up my RAM, which usually improves performance.


Are you absolutely sure this system will handle 6GB? According to the Apple site, the max is 4 GB.

Also, if 6GB works, will 8GB work? I would rather go to 8GB, and use two 4GB modules, instead of one 4 and one 2 GB.

Mar 9, 2012 7:42 PM in response to iMac39

I'd go with 4 GB or the recommended 6 GB from OWC - better yet, chat live with them and ask if there is a noticeable difference between 4 GB vs. the 6 GB (matching modules vs. a 4 + 2 mix). Since they're the ones who've tested this, they should have the answers and of course will work with you.


Here is the info for your model - and yes, it's 6 GB max:


http://www.everymac.com/systems/apple/imac/stats/imac-core-2-duo-2.4-24-inch-alu minum-specs.html

Jan 18, 2016 1:36 AM in response to ScooterG

ScooterG wrote:


Has anyone done this upgrade and found an increase in performance? I've got Yosemite running on mine with 4gb and it's so slow that it's almost unusable.

I'm same machine :

  • Model Name: iMac
  • Model Identifier: iMac7,1
  • Processor Name: Intel Core 2 Duo
  • Processor Speed: 2.4 GHz
  • Number of Processors: 1
  • Total Number of Cores: 2
  • L2 Cache: 4 MB
  • Memory: 4 GB
  • Bus Speed: 800 MHz
  • Boot ROM Version: IM71.007A.B03
  • SMC Version (system): 1.21f4


And also am struggling with it being too sloooowwww.

Can't imagine going from 4GB to 6GB (the max per OWC, Apple max spec is 4GB) will truly matter...

Jan 18, 2016 8:06 AM in response to mtbdudex

The newer OS versions are optimized to run on newer processors, graphics cards, and lots of RAM. Your machine is a 2007 - that is, in electronics, very old. It's great that it is still working, but you cannot expect a seamless performance trying to run the latest OS. Any increase in RAM will help a little; you can also help by eliminating all login items, only have one app open at a time, do not open too many tabs in a browser, delete browser cache and history at least once a day. But, at the end of the day, it is a slow processor, so it will not run the latest OS as fast as a newer machine would.

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iMac 24 Maximum Memory??

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