Apps eat my mac memory!!!!

[Black.Infinity]

I'm trying to understand some virtual memory strangeness I'm seeing.

After a reboot, I have lots of free memory available. After a while, the amount of inactive memory increases until there's hardly any free memory left, at which point my system starts getting lots of pageouts.

What is confusing to me is that this condition persists even after I kill all my applications. Even with no applications running, Activity monitor reports a large figure for inactive memory.

It seems to me that when a an application process is killed, its physical pages should be returned to the free pool, and not left around
as inactive.

Or perhaps that's not what's happening, perhaps some hidden process is eating all my virtual memory.

Does anyone have an explanation for why this happens?

Thanks

 

[iBookG4user]

I believe that the Mac continues to store the most used portions in memory even after the application is quit. That's why an application starts faster the second time it is opened than the first. Although I could be wrong. A good way to clear up the memory is ifreemem or repairing permissions also should be able to achieve the same goal.

 

[richard.mac]

this is a common worry here and you'll find many threads discussing this by searching.

in a nut shell, inactive memory is filled up over time by apps/processes when they close, so they launch faster the next time.

its normal for a little paging out to be done when your RAM is filled up by inactive memory as its still storing inactive memory for those apps. when you start getting A LOT of page outs, like 20% of your total RAM for example, and most of your RAM is being used by active memory, then you should be looking at getting more RAM.

http://support.apple.com/kb/ht1342
http://hints.macworld.com/article.php?story=20010613140025184

 

[Black.Infinity]

thank you guys i guess i should just go buy more ram

 

[interrobang]

thank you guys i guess i should just go buy more ram

Wow, you're really intent on having unused memory, aren't you?

Okay then, I suggest you buy a few sticks of ram and duct-tape them the outside of your Mac's case. Do not install them in your Mac. That way, you'll be absolutely sure that that memory is "free," and not filled with pesky programs or data.

 

[chrono1081]

OSX scales ram and uses what is available. Free ram is wasted ram.

When I turn on my desktop and have nothing running except the OS, it takes about 4 gigs of ram. If I open Maya, Photoshop, and Unity it jumps to between 6 - 12 gigs. I have 24 gigs of ram total in my system.

Now, if I open the same programs on my laptop, just turning on the machine I will use about 750mb to 1 gig for the OS, if I open Maya, Photoshop, and Unity it will use about 2.5 - 3 gigs of ram. (Out of 4).

Unless you are truely in need of more ram, you should be just fine.

 

[mattraehl]

Wow, you're really intent on having unused memory, aren't you?

Okay then, I suggest you buy a few sticks of ram and duct-tape them the outside of your Mac's case. Do not install them in your Mac. That way, you'll be absolutely sure that that memory is "free," and not filled with pesky programs or data.

Nice.

 

[iSee]

thank you guys i guess i should just go buy more ram

No. To simplify: available RAM == inactive RAM + free RAM.

Page outs aren't bad by themselves, even a large number. You've got to watch page outs as you do things:

If page outs increase a bunch as you perform tasks that you wish were faster, then you will probably benefit from more RAM. Otherwise you probably won't.