Currently using a mid 2012 mac book pro. 8 gb RAM i5 processor Intel 4000 HD. I was wondering if it would be possible to attach an external hard drive just to boost its capability for gaming. Not asking for something high end just decent enough to run games like starcraft on high, heroes of the storm on high. I was wondering HOW to do this? Also HOW much it would cost? I'm sort of a noob to computers though, so please explain in laymen terms.