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OS X Memory Allocation

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dr01dy

macrumors member
Original poster
May 3, 2007
68
2
Hello,

Can someone explain to me how OS X allocates its memory I am confused on a few things.

I have 3 gigs of ram

Wired 482MB
Active 1.01Gig
Inactive 1.48Gig
Used: 2.97GB
Free 32.74MB

Does this mean I am running out of ram or does it mean I have 1.48gig free

Also I notice that I have alot of page in's and not alot of pages out which means its not writing to the hard drive.

Thanks !
 
you need some more ram

you have 32 megs free

when the amount of free ram gets down to about 10 megs then it will start writing to the hard disk and you will see page outs
 
Thanks for the reply I guess I am just doing too much at once. I have eyetv converting a movie and ripping out commericals on another rip and Transmit running at 11000k a sec file transfer.

I will see how it is when the rips are done.
 
dr01dy said:
Thanks for the reply I guess I am just doing too much at once. I have eyetv converting a movie and ripping out commericals on another rip and Transmit running at 11000k a sec file transfer.

I will see how it is when the rips are done.
Click to expand...

No, you're OK.

The 'inactive' RAM is being used to cache various pieces of commonly used data (based on your computer-using habits). Should you need more RAM for a task, the inactive RAM will be used to perform said task. In the meantime, the inactive RAM will speed up tasks like opening commonly viewed windows in the finder and stuff like that.

This is the reason why OS X runs so much faster with more RAM: it caches lots of stuff automatically.
 
I thought it was odd.. looking at my Activity Moniter it says that kernel_task is using 1.59gigs of virtual memory.

Do you think I need to upgrade to 6gigs instead of 3 ??
 
diehardmacfan said:
you need some more ram

you have 32 megs free

when the amount of free ram gets down to about 10 megs then it will start writing to the hard disk and you will see page outs
Click to expand...

This is a false statement. Don't listen to this guy because he's wrong. Inactive RAM & Free RAM added together equals your total unused RAM. You're fine and have 1.48 gigs free.
 
Here's what Apple says about it:

What does all this mean?
This means you shouldn't worry when the Free memory is low. The only time Free memory should be high is right after the computer starts up. As you use applications or services, memory is used and transitions to Inactive. Applications that need more memory will take from the Inactive, but the Inactive is there just in case you need it again. If the combination of Free and Inactive is very low, then you might need more memory.
Click to expand...

Link
 
diehardmacfan said:
you need some more ram

you have 32 megs free

when the amount of free ram gets down to about 10 megs then it will start writing to the hard disk and you will see page outs
Click to expand...

um wrong. please dont bother misleading people. inactive ram is free ram as well. to check if you need more ram, look at yout page in to page outs ratio in activity monitor. if they are somewhat comparable you need more ram

edit: realized i should read entire thread before posting lol
 
Thanks for all the help I understand whats going on now. I have tons of free memory I am really only using about 20% of my total over all.

Thanks again!
 
lssmit02 said:
Here's what Apple says about it:



Link
Click to expand...

That's not what actually happens, no matter what Apple says. Disk accesses apparently eat up RAM into inactive and when Free RAM gets down into the Mb range, your Mac will slow to a crawl. This problem has become considerably more annoying since 10.8.4 and is almost insufferable in 10.8.5 with supplemental. I have 8 GB RAM. I used to have to purge (using iFreeMem) once a week. Now I have to do it several times a day. I tried to pin down the constantly increasing Inactive to an app, and thought I could blame Safari, but it proved futile. Last night out of the blue something started eating RAM at the rate of about 100Mb per minute. This has happened before under different numbers of apps open, windows in Dock, etc. I had to reboot three times in a half hour to stop it. Other craziness was going also.
 
It was here in this 6 year old thread, I thought I lost it in the dryer!:D
 

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MacVidCards said:
Holy exhumations, Batman !!! A 6 year old post !!!

Probably not waiting for an answer anymore.
Click to expand...

Consider users thought 3 GB of RAM was good in 2007 and the answers given. My 2008 new MacPro back then shipped with 2 GB of FB Ram which worked with Leopard fine until the 3 rd. party software and OS X's changed. Even Apple has finally upped base offerings to 8 GB in the 15' iMAC.
 
Last edited:
I think you could benefit from more RAM, though the lack or RAM may not be slowing you down. As you said it is not paging. OS X should use up the inactive before paging and you have over a gig free.

However, more RAM means that more can be cached. Any file that is opened or copied (big files too) ends up in RAM and will stay there as long as there is ram available, they just hang out in the inactive area.

For what I do, I always get the max RAM. Huge payoff for me over time.


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dr01dy said:
Hello,

Can someone explain to me how OS X allocates its memory I am confused on a few things.

I have 3 gigs of ram

Wired 482MB
Active 1.01Gig
Inactive 1.48Gig
Used: 2.97GB
Free 32.74MB

Does this mean I am running out of ram or does it mean I have 1.48gig free

Also I notice that I have alot of page in's and not alot of pages out which means its not writing to the hard drive.

Thanks !
Click to expand...
 
Saltymac said:
Consider users thought 3 GB of RAM was good in 2007 and the answers given. My 2008 new MacPro back then shipped with 2 GB of FB Ram which worked with Leopard fine until the 3 rd. party software and OS X's changed. Even Apple has finally upped base offerings to 8 GB in the '13 iMAC.
Click to expand...

Truly one from the grave. I thought it would take a lot to max out the maximum 8 on my MBP 3 years ago how wrong I was. I'm finding it rather nice with 32gb on the 3,1 now though :D

Most customers now on Mac's or PC's who need a refresh I max out their memory, unless the prices for their type are ridiculous like 4gb DDR2-800 desktop ram
 
I'm settling for 20 GB myself on my 08.

Not that I had any real use for it. But I COULD :)

Another 8 GB would get me to 26GB, but it would be a waste for my usage.
 
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