Clearing caches is certainly important. However, and this will seem like heresy, but I use iDefrag in both my iMac and MacBook. If you have had your Mac for any length of time it is likely pretty fragmented. I have heard all of the stuff about Macs not fragmenting, but they do, not anywhere near as bad as XP, but they do and over time it can slow you performance significantly. I defrag my Macs about once every six months, my Windows machines once every week or two. I believe you can get a trial version of iDefrag. Google it. If you can run it and take a look at your drive. I bet you are going to see a lot more red than other colors. Those are the fragmented files. Like I said, heresy, but I know it works, I use it. Most who bad mouth it never have.🙄