mcsys

Q: 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

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

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  • by labeck,

    labeck labeck Sep 24, 2010 8:43 AM in response to mcsys
    Level 1 (0 points)
    Sep 24, 2010 8:43 AM in response to mcsys
    I've been through 5 sets of brand new 16gb kits and all have cause random shut downs on my 27" imac.

    Its definitely an issue with Apple's firmware or software not liking when 16gb is installed. It takes 2-3 days for the issue to present itself but once it does it happens all the time. Apple needs to fix this.
  • by mcsys,

    mcsys mcsys Sep 24, 2010 10:56 AM in response to labeck
    Level 1 (1 points)
    Sep 24, 2010 10:56 AM in response to labeck
    I just got another new iMac 27" i5 with Transcend 4 X 4GB RAM today.
    It has been running fine for the past few hours. I shall leave the computer on for long hours overnight test.

    None of the previous iMac 27" i5 & i7 installed with 16GB (generic brand) passed the test.
  • by labeck,

    labeck labeck Sep 24, 2010 11:03 AM in response to mcsys
    Level 1 (0 points)
    Sep 24, 2010 11:03 AM in response to mcsys
    It ALWAYS took my machine 2-3 days to show the problem. My last test was with Crucial's 8gb kits, it worked well for three days then crapped out. Its going back, the iMac that is.
  • by myror,

    myror myror Sep 24, 2010 12:24 PM in response to mcsys
    Level 1 (0 points)
    Sep 24, 2010 12:24 PM in response to mcsys
    I've been fine running 12 gigs. I'm taking it in to apple tomorrow for them to look at it as requested by a senior apple advisor.. We'll see what happens..
  • by mcsys,

    mcsys mcsys Sep 25, 2010 7:28 AM in response to mcsys
    Level 1 (1 points)
    Sep 25, 2010 7:28 AM in response to mcsys
    To date, the new iMac 27" i5 with 16GB Transcend RAM does not have kernel panic issue. no shut down or whatsoever.

    Some RAMs information about 2010 iMac 27"
    Apple Original 2GB RAM 1333Mhz
    uses 8 X Hynix 1GB chip set on each side.
    Printed on Hynix Chip
    H5TQ1G83TFR
    H9C 020A
    MWJQ4317

    Photos of Apple RAM
    !http://farm5.static.flickr.com/4089/5023032038_e78c0247e9.jpg!
    !http://farm5.static.flickr.com/4149/5022421743_8d45d5fe7b.jpg!

    Transcend 4GB RAM 1333Mhz
    uses 8 X Hynix 2GB chip set on each side
    Printed on Hynix Chip
    H5TQ2G83AFR
    H9C 013A
    MTJJ3K1591

    Photos of Transcend RAM
    !http://farm5.static.flickr.com/4090/5023030790_2b18ea8d01.jpg!
    !http://farm5.static.flickr.com/4092/5022420547_dcb83a78a4.jpg!
  • by mcsys,

    mcsys mcsys Sep 29, 2010 8:34 PM in response to mcsys
    Level 1 (1 points)
    Sep 29, 2010 8:34 PM in response to mcsys
    After a month of troubleshooting, I finally solved my problem.

    My first batch Strontium 8 X 4GB DDR3 1333Mhz RAMs are not fully compatible to install 16GB on iMac 2010. They work well with 8GB. But with 16GB, iMac shows kernel panic within 10-15 mins. I swapped RAM between 2 iMacs to find out the cause. The iMac 2010 simply could not take Strontium 16GB & eventually the iMacs were set to 8GB for 2 weeks without issue.

    I got in another iMac i5 with Transcend 16GB & did a 24/7 test for 3 days without any issue. I transferred the Transcend 16GB to older iMac i5 & did the same test. Today is the third day & the old iMac i5 is still running perfectly with 16GB.

    I can only conclude that iMac 2010 models are very sensitive & selective to some third party 16GB RAMs.
  • by peterwillem,

    peterwillem peterwillem Sep 30, 2010 12:37 AM in response to mcsys
    Level 1 (14 points)
    Wireless
    Sep 30, 2010 12:37 AM in response to mcsys
    I agree with your final outcome of this issue.
    But , for me, it does not solve the problem. I am stuck with 16 Gig of OWC ram, of which I can only use half.
    RMA it to OWC and ask for refund will cost me a lot of extra money. (transport by Fed Ex= $130,- and vat and import duties another $130,-) .
    Not to mention the buying of 20% more expensive Apple ram.
    So I have to think about this if all that extra money is worth it, moreover because I really don't need all the 16 G of ram. For me it was more a matter of having, a expensive one as it turned out to be.
    So for this moment I find it hardly except able that Companies like Apple and OWC put me into this spot in the first place. Both should do something about it. But I am realistic enough to realize that that will take a long time, if at all.

    peterwillem
  • by mcsys,

    mcsys mcsys Sep 30, 2010 10:49 AM in response to peterwillem
    Level 1 (1 points)
    Sep 30, 2010 10:49 AM in response to peterwillem
    I've 2 different sets of Apple Original 2GB DDR 1333Mhz RAMs that were pulled out from iMac 11,3, They are made of Hynix Chips & Samsung Chips. The Hynix chipsets are similar to Transcend RAM & Samsung chipsets are similar to http://eshop.macsales.com/item/Other%20World%20Computing/1333SAM3S4GB/.
    The RAMs are all made of 8 chipsets on each side

    With reference from labeck's thread, http://discussions.apple.com/thread.jspa?threadID=2588800&start=0&tstart=15
    ,he bought from OWC & Crucial

    OWC
    http://eshop.macsales.com/item/Other%20World%20Computing/1333DDR3S16S/
    Crucial
    http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=769226C4A5CA7304

    From the URLs, I see the RAMs are made of 4 chipsets on each side. I'm not sure whether that is the reason behind it. Crucial RAM is made of Micron chips. No clue what chipsets are used for OWC as sticker pasted on them.

    I suggest you ask to trade off your problematic RAMs & top up to get 4 X OWC 4GB Samsung Factory Original DDR3 PC3-10600 instead.
  • by peterwillem,

    peterwillem peterwillem Sep 30, 2010 3:25 PM in response to mcsys
    Level 1 (14 points)
    Wireless
    Sep 30, 2010 3:25 PM in response to mcsys
    Thx,
    I will look into that tomorrow. Meanwhile I have put 16 G of OWC ram in the iMac and within 7 hours I had the problem again.
    I am trying one last option with the 16 G ram inside, and that is working OSX SL in the 64 bit mode.
    That is supposed to make no difference but I want to make sure that that really is true.

    peterwillem
  • by peterwillem,

    peterwillem peterwillem Oct 1, 2010 8:24 AM in response to mcsys
    Level 1 (14 points)
    Wireless
    Oct 1, 2010 8:24 AM in response to mcsys
    As I expected the 64 bit mode did help either


    quote: From the URLs, I see the RAMs are made of 4 chipsets on each side. I'm not sure whether that is the reason behind it.

    Well the OWC rams I have are made of 8 chipsets each side, just like the Apple rams Hynix&Samsung.
    So the 8 and 4 are not the cause of the problem, I would say.

    I am going to discuss this with OWC and see if I can do some trade, but I want to be sure that the Samsung 16 GB will solve the problem.


    peterwillem


    peterwillem
  • by mcsys,

    mcsys mcsys Oct 1, 2010 9:58 AM in response to peterwillem
    Level 1 (1 points)
    Oct 1, 2010 9:58 AM in response to peterwillem
    My problematic Strontium RAMs are also made of 8 Hynix chipsets each side. Probably is due to different circuit board that made the RAM.

    May I suggest you install 3 X 4GB OWC RAM plus 1 X 2GB Apple RAM, total 14GB to see whether you get the same issue.
  • by peterwillem,

    peterwillem peterwillem Oct 1, 2010 10:55 AM in response to mcsys
    Level 1 (14 points)
    Wireless
    Oct 1, 2010 10:55 AM in response to mcsys
    Well I have just a few hours ago installed 2 x 4 G of OWC ram and 2 x 2 G Apple ram.
    So far no problems, but it is early days.
    In one bank a 4G and a 2 G ram , will that work? Aside from the sudden shutdown issue.
    I always thought that the rams in one bank should be equal in size.

    Anyhow I will await the outcome of my present set up.


    peter willem
  • by grizzly marmot,

    grizzly marmot grizzly marmot Oct 1, 2010 11:13 AM in response to peterwillem
    Level 2 (253 points)
    Oct 1, 2010 11:13 AM in response to peterwillem
    The RAM in the two top slots (closest to the screen) should match, and the RAM in the two bottom slots should match. The banks (as displayed in the System Profiler) correspond to right side and left side. It is confusing. I would put the Apple RAM in the top slots.
    Probably the best design would be 2 rows of 3 banks for this chip. But they have probably figured out some other way to get three memory paths out of the banks.
  • by peterwillem,

    peterwillem peterwillem Oct 1, 2010 11:20 AM in response to grizzly marmot
    Level 1 (14 points)
    Wireless
    Oct 1, 2010 11:20 AM in response to grizzly marmot
    Ok,
    so what mcsys suggested, 3 x 4 G ram and 2x2 G ram will not work, because that means 2 different rams in the 2 lower slots. Right?

    peter willem
  • by peterwillem,

    peterwillem peterwillem Oct 1, 2010 3:25 PM in response to mcsys
    Level 1 (14 points)
    Wireless
    Oct 1, 2010 3:25 PM in response to mcsys
    I have sent a mail about this problem to OWC.I like to quote OWC reaction to my mail:

    Hello,

    +OWC has tested the ram in multiple iMacs of this group and the machines work fine with 16 gb of ram.+

    XXXXXXXX
    +Technical Customer Service Representative+
    +Other World Computing, Inc. (OWC)+
    +OWC.net, Inc.+

    So how come that so many of us have problems with that same ram? What is going on?
    Hope that somebody fromApple or OWC van shed some light on this.
    I obviously X'ed the name of the person in the mail.
    peter willem
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