Kernal panic error with OWC RAM combination

Discussion in 'iMac' started by Tike1994, May 26, 2011.

  1. Tike1994 macrumors member


    Jun 27, 2010
    St. Charles, IL
    I've got a new 2011 27" iMac and I ordered 4GB (2 x 2GB) RAM upgrade from OWC.

    I installed the OWC RAM before I even turned the iMac on for the first time. On the first boot I got a kernal panic error and had to restart. I kept getting the kernal panic errors so I removed the OWC RAM and everything worked fine. I returned the OWC RAM and when I installed the replacement RAM the kernal panic errors started again.

    I tried different combinations of the RAM. The Apple RAM works fine by itself and the OWC RAM works fine by itself, but the only way I could get all 8GB of RAM to work was if I mixed and matched the Apple and OWC RAM (i.e. each row has one Apple stick and one OWC stick), but I thought it was best to have them installed in matched pairs.

    Everything has been running fine for a week, but I'm confused why they only work in that combination.

    I called OWC and they suggested they I run the Apple Hardware Test. I ran the extensive test last night and everything was fine. They also told me that the RAM I originally returned was fine.

    Anyone have any thoughts or suggestions? Should I be concerened that something isn't right with the iMac?

    Thanks in advance!!!
  2. ZeD X macrumors regular

    Apr 26, 2011
    I have had an similar issue.

    Having problem with mixing memory brand is not unsual. It happens frequently.

    Are both with the same clock speed and CL? If not, you will have kernel panic (specially on Mac OS).

    If they are the same, try puting they as the following:

    You have 4 slots.

    Try puting as following: Upper right: OWC, Upper Left: Stock, Down right: Stock, Down left: OWC

    See if it helps.

    If not, you will have to return them, or buy all from the same brand.

    Also, are they all the same size (gb), right?
    Your iMac comes with 2x4gb? Are you sure? I think it came with 4x2gb, or 4x1gb.
  3. Nanker/Phelge macrumors regular

    Dec 6, 2010
    Maybe a fresh install would help? Could be some corrupt code in the booting process making things wacky.
  4. product26 macrumors 6502a


    May 30, 2005
    Perhaps the Apple ram is bad, and doesn't play well with others? It could work fine on its own but causes problems when paired with other ram (perhaps even the exact same kind).

    OR perhaps there is a problem with one of the ram slots in your machine. Try putting one working stable set of ram in the other slots.
  5. Tike1994 thread starter macrumors member


    Jun 27, 2010
    St. Charles, IL
    Thanks for the replies.

    The iMac came with 2x2GB and I bought another 2x2GB from OWC for a total of 8GB. The OWC RAM is supposed to be perfectly matched with the Apple RAM.

    The suggestion of how to install them is how I have them now and it is working fine. Top row is one Apple and one OWC, bottom row is one Apple and one OWC.

    Like I said, it's working fine, but I'm paranoid that something might be wrong and I'm not getting the most performance from the iMac.
  6. ZeD X macrumors regular

    Apr 26, 2011
    Click the Apple button and then "About this Mac".

    If they are 1333mhz, so they are at maximum speed.

    If you want to know for sure if there's any problem, you should test your ram, with memtest or similar. Take a look here.
  7. Badger^2 macrumors 68000


    Oct 29, 2009
    Define "the most performance"? How would you tell the difference?

    What are you doing with your iMac?
  8. Cheffy Dave macrumors 68030

    Cheffy Dave

    Feb 5, 2007
    Sunny Florida, on the Gulf Coast in Homosassa Fl
    I learned , in my PC building days, NOT to mix Ram Makers, just sayin:apple:
  9. Tike1994 thread starter macrumors member


    Jun 27, 2010
    St. Charles, IL
    I wouldn't mix RAM makers if it weren't for the fact that Apple wanted $200 for 4GB of RAM and it was $49 from OWC and everyone says OWC is the best.

    As far as performance, I don't do any heavy lifting with the iMac, but I've noticed that it can hang on starting pages with Flash. For example I follow baseball games on and I had to open and close the gameday page several times to get it to load. My wife also said that the flash games she plays take a long time to load. I know that these could be the result of many things, but the RAM issue stuck in the back of my mind.

    OWC has an Apple RAM trade-in program. Maybe I should trade-in the Apple RAM and get all OWC RAM.

    Thanks for everyone's input.
  10. Benz63amg macrumors 68020


    Oct 17, 2010
    New York, NY
    OWC is not the best, crucial is the best ram maker and they are made by micron which is the same ram that came with your imac
  11. ZeD X macrumors regular

    Apr 26, 2011

    OWC is not the best. and not even closer. They aren't crap also.

    Almost every memory are made on the same factory. There are only feel big brands that are able to create ram chips.
  12. dolphin842 macrumors 65816

    Jul 14, 2004
    To the OP:

    Download it does a much more thorough test of the RAM. I had kernel panics for months with OWC ram even though the Apple Hardware Test passed it... Rember found faults within 10 seconds of testing. If you continue to call OWC, they'll eventually recommend trying Rember as well.

    For what it's worth, the 2 most recent RAM sets I've gotten from OWC have been defective. I'm currently using a generic GSkill set from newegg without any problems.
  13. rkaufmann87 macrumors 68000


    Dec 17, 2009
    Folsom, CA
    KP's that are caused by RAM are usually from 1 of 3 causes:

    1. Incorrect RAM, is the RAM you got exactly what Apple specifies?

    2. Failed RAM, you could have gotten a defective DIMM. Only way to really check is a series of elimination.

    3. Unseated RAM, this is pretty common. Remove and push with both thumbs until the RAM is fully seated.

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