I've had a late 2013 13'' rMBP for almost 2 years now, and now I've been given the old non retina 13'' Macbook Pros for work (but it has i7, 8GB RAM, and 256GB SSD). Initially I dreaded using it because of the horrible screen, but now I'm liking it more than my rMBP because it is just so much snappier and no animations lag. Even a simple command + W, f, enter to open a new tab on Safari and go to Facebook is instant on the old MBP while lags noticeably on my rMBP, to the point sometimes it can't keep up with the speed and searches the letter "f" on Google instead of going to Facebook. Is there a rMBP now that performs like the old MBP's? Or is it OS X just dying under the stress of the retina screen and there's no hope?