I'm trying to get a 16 GB (2x of 8 GB) RAM to boost my computer, even though Apple says that it's only 8 GB on macs, but we know Apple is wrong on that. However, when I searched the online shopping place, they only have 1600 variants.

Can I use DDR3 1600 RAM sticks in a 1067 Mac? …and what are the consequences? and when you buy a RAM, does the PC3-8500 things matter or not?

Hardware Specifications:
MacBook Pro 13″ mid-2010 running OS X 10.9.1 Mavericks
Running on 2.4GHz Intel Core 2 Duo
Currently have 4 GB installed (2x of 2 GB) that is DDR3 1067MHz PC3-8500

  • Whyo you know that Apple is wrong regarding memory expansion of a MBP? – nohillside Dec 28 '13 at 13:28
  • Google "MacBook Pros join the 16gig club". I'll leave you to ohh and ahh. – ideaman924 Feb 25 '14 at 12:51
  • Beware of taking SO-DIMM ram and not DIMM ;) – Matthieu Riegler Mar 11 '14 at 22:11

You could add the 1600 MHz memory for your MacBook Pro even though it's designed for a slower memory (1066 MHz) - it ought to work, but you'd be better off buying from a place that accepts returns. Here's some relevant information from Crucial on memory speeds (emphasis mine):

Memory is designed to be backward-compatible, so generally speaking, you can safely add faster memory to a computer that was designed to run slower memory. However, your system will operate at the speed of the slowest memory module.

In "DDR3-1600 PC3-12800"

  • "DDR3" is the type (and must be the same as what your computer has)
  • "1600" is the data transfer rate per second specified in millions (the technical term is "clock frequency") - "1600" here means it supports up to 1600 million transfers per second - in your case, it will be slowed down to 1066 million transfers per second since that's what your Mac is designed for
  • "PC3-12800" is the name used in the memory industry - 12800 indicates a peak transfer rate of 12800 MB/s (of course, the actual performance in your case would be brought down to 8533 MB/s, matching PC3-8500).
  • I just did that and the Mac just beeped at me. I put back the 4gb and it booted right up. I am returning the 1600 and ordering the 1067. I have been told that Macs are very picky. This seems to be the case. – user72747 Mar 11 '14 at 21:13
  • I just did the same with same macbook, and I got a beep as well. Funny thing is; if I have 1 new ram block (4gb) and keep the old (at 2gb), it can boot fine with 6gb of memory. But if I put in both new sticks, it wont boot and beeps at me. Guess I'm returing the 1600mhz ram and buy the 1066mhz instead – FooBar Jan 22 '16 at 12:41

Just tried this in a mid-2009 macbook pro. It almost works. If you replace only one slot, everything works fine, since "your system will operate at the speed of the slowest memory module", as @MK said. But if you replace both of them at the same time, it will NOT work, since the system will try to operate at 1600 MHz (the speed of the slowest memory module).

Update: Tried it again, but using a different memory, and it did not work at all. It seems that macs are indeed picky. (Both memories were 1600 MHz, 4GB - the one that worked partially was a Patriot, the one that did not work at all was a Samsung).


Most new memory uses low voltage 1.2v. Mac before 2013 is still using 1.5V. Your mid 2010 macbook will not be able to support the 1.2V. Issue is not with the speed


I bought two DDR3 4 Gb Ram ( 8Gb) crucial mac memory 1600, 12800 Mhz to increase the two 2 GB (4Gb) that came with my Mac book Pro late 2012. I have know 8Gb.

The two 2 Gb 1600, 12800 DDR3 Ram Mem that I take out from my Mac book were installed in a Mac 21 Inches late 2009, DDR3 1067, 8500. It works fine and the system tell me that I have installed 1067 RAM me not 1600. No malfunction.


Was able to install four (4) mixed serial 8GB SO-DIMMs of Samsung PC3-12800 (1600Mhz) DDR3 SDRAM memory modules (Samsung Memory sticker IDs listed as M471B1G73DB0-YK0 1338 and M471B1G73CB0-CK0 1251) in a Mid-2010 27" iMac with an Intel 2.93Ghz i7-870 processor. Started up and works without a hitch. Memory under "About this Mac" is reported as "32GB of 1333 Mhz DDR3." Therefore, not reported as its native 1600 Mhz. Trick is to make sure the memory you get supports 1.5V as most of the newer memory is lower voltage (eg., 1.35V or 1.2V) that is NOT SUPPORTED by the iMacs older than 2013. Speed is not the issue. So, some people will report Samsung as working, and others will say it does not. Samsung, like Crucial, Elpida, Kingston, Corsair, etc all make good memory, but even the best memory will not work if it is does not support the correct voltage type. Issue is not with higher speed memory which just defaults down to the lower speed that the BIOS supports. In this case, the 1333 Mhz speed is what is reported. So look up the serials on the manufacturer or vendor website that lists the specs and go from there. Also, be aware that this 32GB max is reported only to work with the i5s and i7s, not the i3s or the older Core 2 Duo processors which max out with 16GB Ram at 1.5V setting.

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