content: Do you have a 2015 model? The previous update (10.11.4) caused widespread freezing usually under load or right after startup, but especially during video playback (an easy way to reproduce the effect would be to load a Youtube video in Safari, without Flash installed, on a separate tab, and closing the tab during playback). It has been suspected that Webkit might have a bug, or the Intel video drivers might be outdated, or that, since the problem doesn't seem to appear to pre-Broadwell CPUs, there is a flaw in the architecture. No word from Apple about the issue at all. This has been going on for 2 months, since the 10.11.4 update was released. Now, people are testing this new update and reporting no crashes or freezing. But, there's a catch: the issue can be as frequent as 10 times a day or once every week. What version are you on right now? If you are on Mavericks, I would wait for a few days until there's some confirmation that the freezing issue is resolved. I find El Capitan mostly good, I'm a very casual user, my main is a PC. You should keep in mind that some users on old Mac models find it slow, be it graphics, or load time. Some say it's better than Yosemite, some say it's worse than 10.0 Forgot this, in case you want to see how people investigated: http://forums.macrumors.com/threads/macbook-pro-2015-with-osx-el-capitan-10-11-4-system-wide-freeze.1963711/