10-28-2005, 01:26 PM

Hey guys-

I don't know if anyone else's Mac does this, but usually whenever I open a new app it will go straight for the free RAM instead of the inactive RAM. Then after I cloes said program some amount will go to the inactive RAM. Usually if zi've been working long enough, I can end up with like 80MB of free RAM and over a GB of inactive RAM. And the apps still seem reluctant to use the inactive RAM at that point, since I've had scenarios where I had 800+ MB of inactive RAM and actually had page outs according to the system monitor. On top of that, I usually have to get the free RAM basically depleted to even have the system start using inactive RAM and free up some of it. Anyway, does anyone know if there's a way to free up the inactive RAM? Also, is this something just with me or are other Mac users with 10.4.2 experiencing this? I have a 512 stick from Apple and a 1 GB stick from Crucial in there if it helps any. Thanks in advance!

10-28-2005, 04:04 PM

Yeah, I'm a bit baffeled as to how OS X handles memory at all. When you look at the system status there's like four different catagories of RAM and I have no clue which categories would be comparable to ram which is straight up used and not used.

10-28-2005, 04:39 PM

Originally Posted by RChickenMan

Yeah, I'm a bit baffeled as to how OS X handles memory at all. When you look at the system status there's like four different catagories of RAM and I have no clue which categories would be comparable to ram which is straight up used and not used.

Free RAM and inactive RAM are the unused categories.

10-28-2005, 06:17 PM

As far as I know, inactive RAM is used incase the application that was using the memory needs it again, if an application that has inactive RAM is started up again, the inactive RAM already has information loaded into it that helps the application run faster. I also believe if you have run out of free RAM then your system should then start using some of the inactive RAM.

Maybe someone else can clarify all this though.

10-28-2005, 11:33 PM

http://www.desertsol.com/~kevin/free/

Summary of the terms "wired", "active", "inactive", "used", "free", ...

Wired

= memory allocated that shouldn't/can't be swapped/paged out (ie its locked into memory -- possibly portions of the OS code for example).

Active

= allocated memory that has been accessed during last N seconds.

Inactive

= allocated memory that hasn't been accessed during last N Secs (quite likely to be first candidates for being swapped/paged out if memory being demanded). [I always think of Inactive memory as the memory used by caches]

Used

= Wired + Active + Inactive

Free

= memory that isn't allocated to any process or the kernel.