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Draeconis

macrumors 6502a
Original poster
May 6, 2008
987
281
Hi chaps,

I bought 2x 4Gb RAM sticks for my 15" 2.4Ghz i7 Late 2011 MacBook Pro a while ago. More recently I upgraded to 16Gb, and have the 2x 4Gb sticks spare.

My sister has a 15" 2.3Ghz i7 Mid 2012 MacBook Pro, which she got with 4Gb RAM, but she's regularly exceeding it.

My RAM modules run at 1333Mhz
Hers run at 1600Mhz
Both are 204-pin SODIMMS
Both are DDR3

Electrically they look identical, barring the speeds. Would my 2x 4Gb sticks work in her 2012 MacBook Pro?
 
She should use 1600 MHz RAM. It may work, but may be unstable (cause crashing). Or, it may not boot at all with that slower, 1333 MHz RAM.
 
It takes all of 5 minutes to give it a whirl. Worst case scenario is that it refuses to boot. Put the old sticks back in and chalk this off as a failed experiment.
 
Hi chaps,

I bought 2x 4Gb RAM sticks for my 15" 2.4Ghz i7 Late 2011 MacBook Pro a while ago. More recently I upgraded to 16Gb, and have the 2x 4Gb sticks spare.

My sister has a 15" 2.3Ghz i7 Mid 2012 MacBook Pro, which she got with 4Gb RAM, but she's regularly exceeding it.

My RAM modules run at 1333Mhz
Hers run at 1600Mhz
Both are 204-pin SODIMMS
Both are DDR3

Electrically they look identical, barring the speeds. Would my 2x 4Gb sticks work in her 2012 MacBook Pro?

It will definitely work, the memory will run at 1333mhz instead of 1600mhz which translates to a real life decrease in performance of about 2% ie it won't be noticeable

I was doing exactly the same thing as you propose.. So if you need the extra memory, just do it.

----------

She should use 1600 MHz RAM. It may work, but may be unstable (cause crashing). Or, it may not boot at all with that slower, 1333 MHz RAM.

Nope .. Will definitely work and no instability
 
Thanks for the answers chaps! I assume it'll just run the RAM at 1333Mhz, but I just wanted to double-check, since this isn't my laptop I'd be trying it out on. :)
 
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