Mac OS X Memory Usage
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This article describes how to interpret Mac OS X's memory display in Activity Monitor.
The "Problem"
Although applications are terminated, memory doen't get freed...or so it seems...
- Memory usage when maaany applications are running:
Free: 1.07GB
Wired: 1.39GB
Active: 4.37GB
Inactive: 1.16GB
Used: 6.92GB - Memory usage after maaany applications have been terminated:
Free: 2.30GB
Wired:139GB
Active: 3.48GB
Inactive: 856M.6B
Used: 5.69GB
Although applications are terminated, memory doen't get freed... - Memory usage after purge:
deep-thought:myScripts heiko$ purge
deep-thought:myScripts heiko$
Free: 3.19GB
Wired: 1.38GB
Active:3.02GB
Inactive: 419.1MB
Used: 4.80GB
The "Why"
When memory get's freed, it doesn't immediately appears as "free", instead its "inactive" and is used as kind of cache in case the same data will be reused soon (i.e. re-launching the terminated apps). purge "frees" this inactive memory immediately, but this might be contra-productive.