Use Activity Monitor to read system memory and determine how much RAM is being used (OS X Mountain Lion and earlier) - Apple SupportUse Activity Monitor to read system memory and determine how much RAM is being used (OS X Mountain Lion and earlier) Learn how to use Activity Monitor to read system memory and determine how much RAM is being used. Refer to this article if you're using OS X v10.8 Mountain Lion or earlier. If you're using OS X v10.9 Mavericks or later, refer instead to How to use Activity Monitor. OS X has very eff
