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mcsys Author

Level 1

2 points

Problem with 16GB on 2010 iMac 27" i5 & i7.

I've 8 X 4GB 1333Mhz DDR3 RAM, latest 2010 iMac i5 & i7.
Trying to install 16GB on each iMac.

1. Both work well with 2X2GB.
2. After installing 4 X 4GB RAM , they freeze, cursor spinning ball or kernel panic within 10 to 15mins.
3. Removed all RAMs & installed another batch of 4X4GB, same problem.
4. Installed 2 X 4GB RAMs, they work well.
5. Repeat step 4 with the rest of the 6 pieces of 4GB, they work well with 8GB.
6. Also tested with 4 X 2GB, they work well.

I can only conclude that the new 2010 iMac 27" does not support 16GB well. No doubt it recognizes 16GB at "About This Mac" but it freezes after 15mins. I suspect is due the firmware issue.

Anyone else have the same issue?

Found similar problem at http://discussions.apple.com/thread.jspa?threadID=2567543&tstart=15

MacBook Pro, Mac OS X (10.6.4), iMac

Posted on Sep 4, 2010 3:13 AM

125 replies

Arno V.

Level 1

0 points

Feb 20, 2011 8:58 AM in response to mcsys

PROBLEM SOLVED FOR ME

So I finally think I can safely say that the problem is gone for me. No freezes, loud speaker screeching sound or just black screen. My iMac has been running for the past 11 days non-stop (no reboot, no suspend) with some heavy graphic manipulation among other things.

I used to have 2 different types of RAM but same brand (OWC), all bought at a different time (one in August, one in January). Since OWC has a lifetime warranty, I contacted them and ask them if they could replace the first batch (2x4Gb) with a more recent one. They accepted promptly and as soon as they received my old ones, they sent back the new ones (at no cost to me) immediately!

I have been running with 16Gb of RAM for the past 11 days and haven't experienced any freezes

YAY

I hope my experience can help!

Pic of the new RAM (flickr): http://bit.ly/gqkeS5
Link of the new RAM at OWC: http://bit.ly/fxLUeR
Arno

Mar 6, 2011 12:08 PM in response to Arno V.

I updated my Imac to 16gb using Crucial ram, and whilst everything was ok before, I started suffering shutdowns.
After 2 weeks on making a note of temperatures etc, I had enough.
Bit the bullet and bought 16gb of Apple ram.
Its been 2 days now and so far its been ok and also all temperatures are down.

Mar 16, 2011 12:19 PM in response to wildwestie

maybe an idea is to force OS X to boot on 64bits (mine was booting on 32 bits)
Just tried this, waiting for results

sorry if it's been discussed already

Mar 21, 2011 7:59 AM in response to mcsys

So finally have Hynix Ram in, and the crashes have stopped. I have tested the system for a week or so and can now load multiple projects in photoshop and run pro tools, logic etc with no crashes at all.

Interestingly with the OCZ ram photoshop could only assign itself 6.8 ish GB of ram. With the Hynix it can assign itself over 10!

I can also confirm that idle temps seem to be down since dropping the OCZ....

All very strange my Macbook Pro loves the OCZ ram it has....

--

speedtoxic - I had already tried both 32 and 64 bit kernel, made no difference whatever was selected.

Tank9 - my OCZ passed memtest also, but so does my new Hynix...

David Prats Juan- I had crashes with any configuration of OCZ and factory Hynix or Samsung chips... I even tried just 1x 4GB of OCZ and still got crashes. System was stable as anything with 2x 2Gb Hynix or Samsung

Hope this helps all you suffering people out there

Message was edited by: DJ Nasty Fingers

rodevrie

Level 1

0 points

Apr 7, 2011 7:17 AM in response to DJ Nasty Fingers

Pffff....... I just bought and installed 16 GB Kingston memory and get the freezez. I wish I read this before I did. :-((((

depecher

Level 1

5 points

May 20, 2011 10:08 PM in response to mcsys

I use the original 4gb that came with the iMac, and 3x4gb crucial ram. Never froze once. Been running 16gb for months, no freeze.

babowa

Level 9

78,115 points

May 20, 2011 11:47 PM in response to depecher

I'm curious: you said you use the original 4 GB plus 3 x 4...... as far as I know the iMacs come with 2 x 2 GB (using 2 slots) with 2 slots available (at least that's what the tech specs say and mine had 2 x 2).

So how did yours wind up with 1 x 4 GB from the factory?

gary23

Level 1

0 points

Aug 26, 2011 5:27 AM in response to mcsys

I installed 16 gigs of ram from OWC last friday.. (So mid August,2011) in my Mid 2010 iMac 27inch and I have not experienced any slowdowns or problems at all

dunno99

Level 1

0 points

Sep 6, 2011 12:53 AM in response to mcsys

New 27" iMac. Been having problems after upgrading to 16GB Mushkin 976647A. Uninstalled 8GB, and the remaining 8GB fine. Swapped those 8GB with the remaining 8GB, and that was fine too. Reinstalled 16GB, and everything was haywire again. Don't think the modules are screwed up...more like, something wrong with the iMac itself.

Either way, easiest way to repro this for me was installing Windows 7 in Parallels. Dies sometime during the "Expanding files" stage. Another way I found is to create an ISO of a large DVD, then do an MD5 checksum. The two checksums will come out differently (make a control version without the 16GB first, of course =). Maybe I should write a small program to open up the two files to see where the memory corruption is happening....

petran81

Level 1

0 points

Sep 24, 2011 6:19 AM in response to mcsys

Hi!

I have 27'' imac i7 with 2x2 GB hynix ram

I try to update my ram with 4x4 GB hynix ram and after some days crashes.

what can I do for this proplem?

babowa

Level 9

78,115 points

Sep 24, 2011 8:20 AM in response to petran81

I've not heard of any problems with Hynix RAM (which is the same brand Apple has been using, so:

did you seat the RAM correctly (all of them)?

do all 4 modules show up in System Profiler as ok?

have you tried eliminating one by one to see if there might be a problem with one of them?

And, I had a problem with one of my RAM slots on my Macbook - it was the slot, not the RAM that was causing the problem, so does one of your four slots feel or react different when trying to seat the RAM?

And, you might want to run Apple Hardware Test:

http://support.apple.com/kb/HT1509

petran81

Level 1

0 points

Sep 24, 2011 10:11 AM in response to babowa

they seat correctly yes.

and all modules show up in system profiler.

I didnt try to use them one by one.

The two slots they are ok because I run it more than two months with the 2x2GB and have no problem.

I will run the test

thank you!

petran81

Level 1

0 points

Sep 24, 2011 11:20 AM in response to petran81

I run the test and didnt have a problem

petran81

Level 1

0 points

Oct 18, 2011 1:11 PM in response to petran81

same problem again 😟

DylanRhea

Level 1

127 points

Nov 17, 2011 11:46 PM in response to petran81

Has anyone successfully installed 4x4 (16gb Total) OWC RAM on a new 27" iMac i7, late 2011 model? Have the issue been resolved as per the posts from 2010 and early 2011?

Problem with 16GB on 2010 iMac 27" i5 & i7.