Difference between PC3-10600 and PC3-8500 Memory

Posted on 2016-07-21
Last Modified: 2016-07-22
 I have 2010 Apple MacBook Pro 15" Laptop that came with 4GB (2GB x 2) of RAM. The laptop has two memory slots and I like to upgrade it to 8GB (4GB x 2).
The current memory spec is DDR3 PC3-8500 DDR3-1066 SODIMM CL7, 1.35V, 512Meg x 64

Will the following memory work on my MacBook?
8GB (4GB x 2) DDR3-1333 (PC3-10600) CL9 SO-DIMM 1.5v ?

Question by:sglee
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Expert Comment

ID: 41724050
You are always able to put faster RAM of the same kind in the same slot.  Whether it will support the faster speeds depends on the model.

You can look up your exact model by entering your serial number on
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Accepted Solution

Davis McCarn earned 500 total points
ID: 41724612
PC3-10600 is slightly faster than PC3-8500; but, you wouldn't really notice the difference and I don't think what you posted will work.  Not because of the speed difference; but, because you currently have DDR3L (1.35 volt) installed and most PC's that use low voltage memory won't recognize non-L parts.
The right answer is to either enter your serial number in serialband's link above or click on the Apple in the top left of your screen and choose About this Mac.  In the More info window, it will say something like MacbookPro6,2 which will identify your model and searching that will show you your upgrade options.

Author Comment

ID: 41724643
I am so much concerned about voltage as long as THEY FIT in the slot.
Will 8GB (4GB x 2) DDR3-1333 (PC3-10600) CL9 SO-DIMM 1.5v fit in existing memory slot?
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LVL 42

Expert Comment

by:Davis McCarn
ID: 41724739
Most 1.5 volt parts will not work in a 1.35 volt, low voltage socket! (Been there, done that)  Yes they will physically fit; they just won't work.

Author Comment

ID: 41724784
Thanks for the information about the importance of matching voltage.
How important is it to mach CL -  CL7 vs CL9?
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Assisted Solution

by:Davis McCarn
Davis McCarn earned 500 total points
ID: 41724834
Many Windows PC's are very forgiving about installing the wrong memory (i.e. PC3-10600 memory works; but, only runs at PC3-8500 speeds because of the specific hardware) though almost none of them like wrong voltages (1.35 vs 1.5).
Apple's though can be extremely persnickety about exactly what hardware will work and, behind the scenes, every item of hardware is explicitly identified each time you turn the unit on.  I have been servicing PC's for over 40 years (I became an Apple authorized technician in 1978) and I learned, early on, to dot my I's and cross the T's, especially with Apple products, an awfully long time ago.
You can probably buy generic memory, saving a lot of money; but, you had better start with that MacbookPro6,2 (or 7,1 is also a 2010 model) identifier or you stand a very good chance of not having it even try to boot when you put the new memory in.

CL7 or CL9 refers to the parts latency and is the number of clock cycles defined as part of that parts timing.  Don't worry about it; use the Mac's specific model type!

Author Comment

ID: 41724920
Thanks for the information and I appreciate it.

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