I have this awesome MacBook Pro with 8 GB of RAM. When I open up Activity Monitor it would seem that I have plenty of RAM available, but my computer seems to prefer to use virtual memory for many things. Why is this? Is there a way to change it? Would it be wise to?

Also,I seem to have 7 GB of pageins and no pageouts. Is that normal? That's a lot of data.

  • 1
    See this question. When it says virtual memory, it does not mean it is using your disk as RAM (the swap size does). No pageouts also indicates that it isn't storing RAM on disk.
    – ughoavgfhw
    Commented Sep 10, 2012 at 23:05
  • Page ins and Page outs are related to SWAP and NOT VM
    – Alexander
    Commented Sep 10, 2012 at 23:22

1 Answer 1


You seem to misunderstand virtual memory. Virtual memory is simply a mechanism that the OS uses to make it look like each program has its own, extremely large (4GB on 32-bit, 16 EB on 64-bit) address space. It also provides a way for the OS to use paging, all while making it look like (to applications) only real RAM is being used. In short, it's only an abstraction, and the "Virtual Memory" stats in Activity Monitor are meaningless (for 99% of use cases). You should not be worried at all about whatever number appears there, because it has nothing to do with whether "real" RAM is being used or not.

About your paging stats : you gave no details on how you use your system, so it's hard to know whether something's wrong or not, but I wouldn't be alarmed by a value of 7 GB. Also note that the reported values are Page ins/outs since boot, so if you keep your laptop on all the time like me, it's no wonder that the number accumulates after a while.

  • The trouble happens when you start getting lots of page outs. Page ins are low cost when there's free physical memory. Page outs are caused by the OS needing to page something in, but it has no free physical memory and must swap something out first. With 8GB RAM, this is non-trivial.
    – alesplin
    Commented Sep 11, 2012 at 18:45
  • A good starting point for measuring live paging stats with vm_stat can be found on this answer
    – bmike
    Commented Sep 17, 2012 at 14:42

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