Hi guys, I hoped someone can help that once had the same problem. I have a mid 2012 Macbook pro 13" standard setup. So 4gb ram, 500 gb hdd etc. A few weeks ago, without any reason my macbook started running extremely slow. Unusable slow, with the rainbow icon being permanently there. First I thought that it was a faulty hd. Though the hd seems fine, ran Smart utility and everything was okay and booting the macbook using the same hdd but only externally, it ran fine. Pram and SMC reset did not help. Filevault is turned off. Also formatted the hdd and clean installed Yosemite. Nothing worked. I was hoping someone has any idea what the problem could be. Thinking it must be the logic board, but could that be the problem of a macbook slowing down? Or maybe it could be a faulty hd cable, though I read an article that stated that a faulty hd cannot be the reason of slowing down. It works or it does not, with speed not being a variable that could change because of this cable. Already checked the costs of a new logic board, that would be 700 euro and that simply is not worth the hassle. Any Thoughts on what to do? Will be appreciated!