Ok, so I have a late 2013 Macbook. Which ran awesome until I installed Mavericks on it. Yes it was nice getting the features but Mavericks seems to be a memory hog on my computer. I mean I have max RAM and I've had it complain about running out (WTF?!, 16 gb of ram and I'm just internet browsing mostly should not kill my RAM!). It takes longer to start up now and has random pauses (it is getting worse too) when doing stuff...even typing sometimes. I'd honestly say this is my least favorite Mac OS since 8.0 (or 8.5, can't remember which. ONe of those was such a system hog that when they released the next one that fixed the problems it was a huge difference in performance. BEfore then I always attributed new OS running a little worse to it just being my computer being old. For 8.5 or which ever one it was, it was obviously a badly optomized OS). Have people experienced whether El Capitan makes your computers run better or worse than on Mavericks (even if it is tolerable to you I don't want to upgrade if my computer is going to get even worse. I wish I could go back to the original OS). Edit: I don't know why I had Mavericks in my head, it's Yosemite that is pissing me off (I guess Mavericks was what my computer had when I got it). Mavericks ran great on my computer (I think that was the one it came with).