I found Macs which had:
16GB RAM installed
8GB RAM installed, but running on 1600MHz instead of 1333MHz (link in dutch)
Is it possible to put 16GB running at 1600MHz in my Mac?
If you've done this, please post a screen shot.
Apparently you need a Macbook Pro with an i7 processor of at least 2.2GHz or more in order to use memory running at 1600MHz.
- Macbook Pro 8,2 early 2011 - 2.0GHz i7 quad
edit: I recently found this sleepimage. Basically it's just a swap file of your RAM. so your mac can 'sleep'. But when you install 16GB you're gonna have a 16GB RAM file sitting on your disk as well. Which you can safely delete but it will be recreated when your mac goes to sleep. just something to consider when your working with limited disk space.