Please help me understand system memory

ipoddin

macrumors 65816
Original poster
Jan 6, 2004
1,024
80
Los Angeles
I'd like a little better understanding of my memory usage. I go in to Activity monitor (or use a widget) and see "wired," "active," and "inactive"

What does each mean? For instance, currently I have Dashboard, Firefox, and Quicksilver running and here are the results:

Wired: 229.26mb
Active: 388.96mb
Inactive: 631.56mb

Free: 797.59mb

I'm using 1.2gb of memory and that seems like a lot. Now I do have alot of widgets, so I could try disabling some. However, right now, I'd just like to understand what all the memory readings mean. Thanks.
 

emptyCup

macrumors 65816
Jan 5, 2005
1,482
1
Wired: Memory that is currently in use for something so important that the application requires it to be in memory at all times

Active: Memory that is currently in use but which may be swapped out to disk when necessary (and brought back when needed)

Inactive: Memory that was in use but is not currently needed. It constitutes a cache of things that can be accessed quickly if they are needed again or disposed of if the space is needed for something else.

Free: unused. Typically only high after a restart. Free and Inactive together make up what most people think of as Free (available).
 

ipoddin

macrumors 65816
Original poster
Jan 6, 2004
1,024
80
Los Angeles
emptyCup said:
Free: unused. Typically only high after a restart. Free and Inactive together make up what most people think of as Free (available).
Ah. That makes it clearer. Thought something must be wrong. Thanks.
 

WildCowboy

Administrator/Editor
Staff member
Jan 20, 2005
17,466
1,452
For future reference, here is the official word from Apple on memory. But yes, emptyCup gave you a great explanation.
 
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