Confusion about recommended clock speed Recently  I have been facing issues with multitasking with my Macbook Pro (13-inch, Late 2011) and decided to upgrade my RAM. Now, my laptop currently has 2-2GB DDR3 1333 MHz for a total of 4GB. I wanted to upgrade my RAM to a total of 8GB.


Here's my confusion:

The Apple Support page on upgrading RAM recommends 1600MHz for my model. 

So what should I do? Stick with 1333MHz or buy 1600MHz?I'm willing to spend the extra money if the motherboard will be able to utilize faster memory. Will I notice a difference? Also, what about warranty? Will my warranty be voided by installing either of these myself?
The MacBook Pro: How to remove or install memory article you linked does not state 1600 MHz for MacBook Pro (13-inch, Late 2011)!   It actually states "PC3-10600 DDR3 1333 MHz type RAM".  I would not purchase 1600 MHz RAM and instead purchase what is specified.

As to voiding the warranty for upgrading the RAM yourself, I was told at an Apple store that it wouldn't however If you live close to an Apple store and your Mac is still under warranty I'd suggest you have them do it unless you have the proper tools and knowledge to accomplish the task.