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amitdoc2b

macrumors 6502a
Original poster
Feb 25, 2008
938
81
Looking at the memory on iStatPro of my new MBA, it shows 900mb are wired, 2GB are active, and 1GB is inactive. This leaves me with like 100mb of free memory. What do they mean by "wired" memory and "inactive" memory? I'm not doing anything intensive so I am surprised about my very little free memory.
 
Thank you for this. So what happens when I need more memory with only 100MB free memory left that becomes used up from my original post example. Does the computer start using the memory space from the inactive memory portion and delete what was in there?

If it needs more than you have it will begin paging to the SSD. With the SSD in the MacBook Air you will notice it less than on a traditional HDD.

This is what SWAP files are. SWAP is SSD(HDD) space that is being used as a temporary home for stuff that can no longer fit in memory. Ideally you want Page Outs to never be more than 10% of Page Ins.
 
Thank you for this. So what happens when I need more memory with only 100MB free memory left that becomes used up from my original post example. Does the computer start using the memory space from the inactive memory portion and delete what was in there?

Correct, the Inactive Memory is the RAM space ready to be reused when there is nothing Free. So, in your case, if you had only 100MB free and the system needs >100MB, then it would bite into the Inactive Memory like it is supposed to. So, in reality, you have 1.1GB of RAM to be used.

Nothing to worry here.
 
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