I know I havent discovered anything new here but I wonder if someone can explain to me why every time after major OS upgrade my computer slows down, overheat is unresponsive etc. The same apply to my IPhone 4 and 4s and even my work laptop with Win7. I do understand what the processor is or RAM and power associated with it but on another hand new OS apparently should be faster, better and more efficient. But is it? Or perhaps this is new silent way make all devices slower in order to make the customers to upgrade again? It used to (still is but hard to prove), not long time ago companies design devices so they cant live no longer than desired life span but now is this new way to screw us again? Call it silly conspiracy theory but after years of being fan of Apple now I could see the difference. I got iPhone 4 and 4s and after iOS7 they cant respond properly. Should I replace them for iphone 5 just for what?...useless fingerprint. There is nothing wrong with my current iPhone. The same for Maverick on my high spec 2011 iMac 27. My laptop with win7 bought 16 months ago is barley follow my keystrokes after forced Microsoft updates. Believe me I have cleaned and reinstall my iMac, MBA and win laptop and honestly no much difference. Can someone explain to me this phenomena so I can think that it is perfectly ok spend $1000s every couple of years to make their software on theirs hardware working 100% efficiently.