the_bart123
Level 1 (4 points)
Desktops

Q: MacBook Pro 15" 2011 slow with 2x 4GB RAM - but ok 1x 4GB

Hi everyone

 

I've upgraded my MacBook to 2 the same sticks of 4GB Samsung PC3 10600S (1333MHz) RAM and when 2 of them in - MacBook is slow in Youtube - even pointer - when with just one 4GB stick - everything works fine

 

When I insert other one to check if its faulty - works great :/  same with one stick in first or second slot

 

Whats wrong?

MacBook Pro, OS X Yosemite (10.10.4)

Posted on Jun 24, 2016 1:08 PM

by leroydouglas,Solvedanswer
leroydouglas leroydouglas
Level 7 (24,036 points)
Notebooks
A:

the_bart123 wrote:

2 the same sticks of 4GB Samsung PC3 10600S (1333MHz) RAM

 

2 of them in - MacBook is slow in Youtube

 

when with just one 4GB stick - everything works fine

 

 

Most likely a bad stick of RAM.  If you swap banks with the operating RAM and it stops working then it is a bad bank.

 

The fix for a bad bank is a CPU replacement.

 

The fix for a bad stick is replace it with a good one.  Most reputability dealer have a lifetime guarantee on RAM.  Contact them once you sort it out.

 

Verify you have the correct spec on your new RAM using Crucial  http://www.crucial.com/usa/en/systemscanner

 

If they are not working together then I would replace both sticks for a "better" matched pair—not your fault.

Posted on Jun 24, 2016 1:17 PM

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the_bart123

Q: MacBook Pro 15" 2011 slow with 2x 4GB RAM - but ok 1x 4GB

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  • Helpful answers

  • by leroydouglas,Solvedanswer

    leroydouglas leroydouglas Jun 24, 2016 1:17 PM in response to the_bart123
    Level 7 (24,036 points)
    Notebooks
    Jun 24, 2016 1:17 PM in response to the_bart123

    the_bart123 wrote:

    2 the same sticks of 4GB Samsung PC3 10600S (1333MHz) RAM

     

    2 of them in - MacBook is slow in Youtube

     

    when with just one 4GB stick - everything works fine

     

     

    Most likely a bad stick of RAM.  If you swap banks with the operating RAM and it stops working then it is a bad bank.

     

    The fix for a bad bank is a CPU replacement.

     

    The fix for a bad stick is replace it with a good one.  Most reputability dealer have a lifetime guarantee on RAM.  Contact them once you sort it out.

     

    Verify you have the correct spec on your new RAM using Crucial  http://www.crucial.com/usa/en/systemscanner

     

    If they are not working together then I would replace both sticks for a "better" matched pair—not your fault.

  • by OGELTHORPE,

    OGELTHORPE OGELTHORPE Jun 24, 2016 1:24 PM in response to the_bart123
    Level 9 (52,725 points)
    Mac OS X
    Jun 24, 2016 1:24 PM in response to the_bart123

    delete.

  • by the_bart123,

    the_bart123 the_bart123 Jun 24, 2016 1:28 PM in response to OGELTHORPE
    Level 1 (4 points)
    Desktops
    Jun 24, 2016 1:28 PM in response to OGELTHORPE

    every single RAM stick in every one slot works great (MacBook fast) but when both sticks in = slow MacBook (very visible in Youtube 1080p and very slow and jumpy pointer) 

     

    Even Apple did diagnostic and said it passed tests - but it is slow - and offered me very expensive Motherboard replacement

     

    P.S. It passed video test recall

  • by leroydouglas,

    leroydouglas leroydouglas Jun 24, 2016 1:33 PM in response to the_bart123
    Level 7 (24,036 points)
    Notebooks
    Jun 24, 2016 1:33 PM in response to the_bart123

    Even Apple did diagnostic and said it passed tests - but it is slow - and offered me very expensive Motherboard replacement

     

    P.S. It passed video test recall

    Now the details come rolling in.

     

    Put the factory RAM back in, same problem would point to a defective CPU.

     

    However Apple will test with factory spec RAM, not your user upgraded RAM.

     

    I still suspect you have a mis-matched pair. Buying bad RAM is not that uncommon, unless the above test is the same result.

     

    You can ask for the Apple  Depot Repair Service—less expensive way to go, turn around time is 1 week.