Every 15 seconds... or more. On every appiication. If I'm typing it will stop responding for a couple seconds, many times per minute. Scroll over something and it won't acknowledge that I did for a couple seconds, basically anything I'm doing at the time of the freeze will stop working. If I'm scrolling it will stop for a few seconds, same story. The computer is just totally locking up for a second or two at a time. Everything is doing it. I don't mean to be dramatic but Yosemite is literally unusable for me right now. It is driving me nuts. This was never a problem until very recently, starting at maybe the 2nd last Yosemite beta. 2012 cMBP I did a cmd +r and selected reinstall OS X, still happening. Please advise.