Released June 2012 / Core i7 processor with Turbo Boost / Up to 1 GB DDR5 Video RAM

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Which RAM is suitable? 1866 MHz or 2133 MHz DDR3L?

Hi there,

I got these 2 pairs of RAM:

  • 1866MHz DDR3L - 8 GB x 2 Kingston HyperX Impact Black
  • 2133 MHz DDR3L - 8 GB x 2 G.Skill RipJaw

Can someone tell me which one is suitable for my system: MacBook Pro 15" 2.6GHz i7 (Mid 2012)?

Also running with two 2TB Samsung 850 EVO SSD in a RAID 0 setup.

Update (07/18/2017)

1866 MHz running fine & smooth, no problem.

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Update (07/22/2017)

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i also just installed the 2133mhz..and seems ok..

Answered! View the answer I have this problem too

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Happy it all worked out. Enjoy!


Remember you won't get any benefit with the faster RAM here. I would save it for a overclocked system you're building ;-}


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1 Answer

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Your system is spec'ed for: 1600 MHz PC3-12800 DDR3L SDRAM SO-DIMMs (204-pin)

Jumping up to a faster speed RAM won't buy you that much and if you go to far you can in fact create problems! Here's an interesting set of vids you might want to review:

Linus & company do a good job explaining things. While they talk more about desktops the same holds true with laptops with one exception! Unlike desktops MacBook Pro's don't offer any access to the systems timing so what it is is what it is!

This is why buying RAM that is above Apples specs on the most part is wasted and costs you more than you need to spend!

So stick to what is the cheapest option as long as you meet the systems specs. If you already have the 1866 MHz DDR3L then use them.

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Dan, what problems are you referring to? The first 30 (and top) Geekbench scores all have systems using 2133MHz RAM. Are you talking theoretically, or do we have any actual problem cases?


@snakes202 - I think you need to take a second look MacBook Pro (15-inch Mid 2012) Benchmarks GeekBench doesn't list RAM type.

As far as seeing problems, Yes! I've seen issues when people push the RAS & CAS beyond what the system was designed to support.

I would recommend you do some reading on RAM specs


You are looking in the wrong spot...those the are the Geekbench official averages.

Look here:

And are the problems you are referring to about overclocked RAM or stock high speed RAM?


The issue is strictly going to far with the clock speed of the SO-DIMM's CAS latency Stick with the correct RAM modules.

I would strongly recommend you take the time to review the links in my answer.


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