ram upgrades 21.5 imac 2011 mid

Question

Level 1

8 points

ram upgrades 21.5 imac 2011 mid

I have a 21.5 inch mid 2011

I saw that I was able to upgrade with four ram stick slots. So I added the most I could which was 4 8gb ram sticks, seemed to work fine for a month or so until I started getting errors. I removed 2 of the ram stick and computer runs fine. Much later I see the intructions on upgrading ram for my version. It recommends 4 4gb ram sticks with a max of 16gb. Currently, I have 16gb but on 2 sticks. my question is....will this effect performance in any way or does it make no difference?

iMac, OS X Mountain Lion (10.8.3)

Posted on Sep 7, 2013 12:22 AM

Reply

Answer 1

babowa

Level 9

78,580 points

Sep 10, 2013 12:48 PM in response to imacdiddi

Here are the specs for your Mac (and the RAM appear to be the correct specs):

http://www.everymac.com/systems/apple/imac/specs/imac-core-i7-3.4-27-inch-alumin um-mid-2011-thunderbolt-specs.html

Being able to return RAM is extremely important - that's one reason why I only do business with OWC (or Crucial).

You can try 20 GB - I've not tried, so can't say if it'll work or not. Worst case scenario: it won't work and you take them back out. Are the 8 GB modules recognized?

Reply

Answer 2

mende1

Level 10

93,624 points

Sep 7, 2013 12:26 AM in response to imacdiddi

It won't affect performance. A Mid 2011 iMac supports 32 GB of RAM, but Apple says that they support 16 GB. 8 GB modules are supported, so you won't have any problem. Furthermore, if both memory modules are installed on the slots at the top or at the bottom, you get Dual Channel, which increases the memory performance

Reply

Answer 3

imacdiddi Author

Level 1

8 points

Sep 8, 2013 10:02 PM in response to mende1

interesting...but why would apple specify only 16? I saw four slots, went out and got 4 8gb modules and it did work fine for about a month or so, until on startup I would get error's. I unplugged all the externals, which btw was pretty maxed out maybe 10 or more externals...so unplugging it got it to start up fine. Then later it happened again, so I pulled all the externals again, but this time it didn't work.

So an apple tech suggested pulling the ram pulled and it restarted fine. I hoping its not the ram cause then I can enjoy the power of 32gb again, which is great!

Reply

Answer 4

nbar

Level 5

7,037 points

Sep 8, 2013 10:06 PM in response to imacdiddi

The majority of intel Macs support more RAM than Apple specifies. Apple has only subsequently changed the official specs on a few models. This is because Apple has no incentive to do so / they do not produce their own RAM. Mac Computers would have to undergo extensive QT testing for Apple to officially change the RAM specifications. Furthermore, companies like OWC and Crucial have done testing themselves, sell Mac supported RAM, and offer warranties on it.

Reply

Answer 5

John Galt

Level 10

156,692 points

Sep 8, 2013 10:07 PM in response to imacdiddi

Use memory from a vendor known to support Macs. OWC / MacSales and Crucial are the only two with which I have personal experience and can recommend.

imacdiddi wrote:

interesting...but why would apple specify only 16?

When it was engineered only 4 GB DIMMs were available so that was all they could test. Once a Mac's memory specifications are published, Apple does not update them to reflect availability of products that become available later.

32 GB is fine for your mid-2011 iMac.

Reply

Answer 6

babowa

Level 9

78,580 points

Sep 8, 2013 10:12 PM in response to imacdiddi

Where/what brand of RAM did you buy?

Have you run the Apple Hardware test (run in extended mode three times)?

OWC (macsales.com) tested it and found it works with 32 GB RAM whereas Apple's specs state that it supports 16 GB. Being cautious myself, I would only go with something higher than Apple's specs if I bought the RAM from the vendor who tested it, especially since Apple states that each slot supports a 4 GB module.

Reply