The RAM in this machine is PC3-10600 RAM. That&#039;s the same RAM used in the 2010 revision of the 21.5&amp;quot; and 27&amp;quot; iMacs, but different from earlier Apple laptops. PC3-10600 RAM is backwards compatible with the PC3-8500 RAM in older MacBook Pro Unibody machines, but you can&#039;t use older PC3-8500 RAM in this machine.