Will RAM that works in 2012 Macbook Pros also work on older models?

[Qusus]

I want to get this RAM for my old Macbook Pro (MB990LL/A) from mid-2009:

http://www.newegg.com/Product/Produ...-cables-_-na-_-na&Item=N82E16820226280&cm_sp=

Two customer reviews say the RAM works with "mid 2012 macbook pro 13."

Will it also work with my older Macbook Pro?

I recently bought some Crucial DDR3L RAM with identical specs and it did not boot up.

Thank you for your help.

 

[chscag]

The Mid 2009 MacBook Pro models use: 204-pin PC3-8500 (1066 MHz) DDR3 SO-DIMM

The 2012 model uses: 204-pin PC3-12800 (1600 MHz) DDR3 SO-DIMM

As you can see the memory modules are different (speed). Always use the specific memory for your model. Even though the modules may fit, it doesn't necessarily mean that they will work.

 

[Anonymous Freak]

The problem is that DDR3L is lower-power, and *REQUIRES* support from the chipset. A 2009 MacBook Pro needs "plain" DDR3, not DDR3L.

A newer one can also use DDR3, but DDR3L is considered preferred because it is lower power usage, and the newer MacBooks aren't tested/rated for the higher power draw.

As for speed? If you get RAM rated at your systems speed or greater (2009 is rated for PC3-8500 / 1066 MHz) it should work fine. Just make sure the "DDR #" (or PC#) is the same, the pin count is the same, and the speed is what yours is rated for or higher. So no PC2-8500 (which is DDR2,) no PC3-6400 (800 MHz, too slow for yours,) and no DDR3L (low-power.)

 

[Macyourdayy]

Sites like Macsales.com and Crucial can help you select the highest rated RAM that is compatible with your device. For example, I'm running 1600Mhz Crucial chips in my late 2011 MacBook Pro shop since RAM cards supplied with my machine (via eBay, not Apple) were eventually shown to be faulty, causing excruciatingly slow running rather than crashes or kernel panics. The 2011s are rated at 1333Mhz, but the 1600s are correctly identified by System Report and run on many later series Macs.