I have a Mid 2009 Macbook Pro on OS X Yosemite 10.10.5 2.26 Intel Core 2 Duo. 4GB 1067 DDR3 Its running pretty slow and I would like to upgrade the Ram to speed things up a little. How much Ram can I run? Is 8GB the max. If so is there a specific brand or Ram to use or are there any brands to stay away from? Thanks, Richard.