In my hours of research this morning, I feel pretty enlightened about which RAM you can buy for your MAC.
First lesson: you don’t need to buy RAM from the Apple Store.
Also, even with 3rd party brands you don’t need to buy anything branded special “Mac Memory”- you may come to this decision crossroads when you find 2 products with exactly the same specs and one is $10-20 more because it says “Apple”. alust2013 says on 7/31/11: “Don’t buy the “for Mac” one. It’s a waste of money. Just get whatever is cheaper.”
Second lesson: all RAM pretty much comes out of the same factory.
RAM is RAM, and most of it is identical. What differs is the quality control guarantee per production batch. When the factory produces a batch it can certify is best of the crop, Apple places a premium bid on those. If production is off by a micron and the possible error rate goes up (say from 1 in 100,000 -> 1 in 10,000), that batch gets a lower grade (instead of an A, it may be a B+ for example). Apple… or Lenovo, etc. will pass on this (it has its reputation at stake, and will pay for certainty). But each following 3rd party brand will make purchase orders according to the quality level that is in line for their brand name.
Much in the same way- we ourselves could start a RAM brand “Valuetron” and our business model is to buy C+ level RAM- it’s the same RAM and most will function perfectly fine, but there are more flops in the batch.
Note: Camera sales work in much the same way. Wonder why the Canon 5d Mark III is cheaper in an obscure online shop vs. at the trusted retailer? They are selling the same camera, but the trusted retailer will most likely have gotten dibs on a solid A grade production quality score, where the smaller fish bought up the B grade.
Third Lesson: Know which RAM is compatible with your system
There are different physical sizes of RAM. Find out yours by going to “About This Mac” and cross verify compatible settings at a trusted source:
These sites say that:
1) Max working RAM capacity for a mid-2009 Macbook Pro unibody Core 2 Duo etc. is in fact 8GB. Sometimes you can overclock it beyond Apple specifications and use more, but not this time.
2) Size: SO-DIMM 204-pin DDR3. Important because some RAM may be DDR3 but not SO-DIMM (formatted for notebooks), and the number of pins is important and determines the shape.
3) Speed: mid-2009 MacBook Pros are DDR3 1066 MHZ (aka 1067 or 1066.6). It WILL work with 1333 MHZ because RAM is backwards compatible and will just run at the slower speed, but NOT 1600 as noted in Amazon forums and here. Latency is the other part of speed: the amount of delay before executing a process, signified by abbreviation CL. SO-DIMM 1066 MHZ RAM has CL=7, where SO-DIMM 1333 MHZ RAM has CL=9. It takes 7 cycles on 1066 MHZ but 9 cycles on 1333 MHZ. Ultimately this doesn’t make much of a difference since 1333 MHZ probably cycles faster than 1066 MHZ. Read more on Wikipedia: CAS Latency.
My Purchase Decision
I wanted the product immediately, so in the end (for Berlin, Germany options) I purchased Corsair CM3X8GSDKIT1066 XMS3 8 GB PC3-8500 1066Mhz 204-pin SODIMM Laptop Memory from the Cyperport electronics store here in Berlin, but you can grab this off Amazon. Took only a few seconds to install, and it’s working great so far!
If I were fine to wait for shipping, I would order in order of preference:
1) from trusted OWC: 2 x 4.0GB PC8500 DDR3 1066MHz 204 Pin LIFETIME WARRANTY
2) from Crucial CT2CP51264BC1067 8GB 204-PIN PC3-8500 SODIMM DDR3 (4GBx2)