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mrurmil · Jun 23, 2005, 07:18 PM

Hi all,

I have a Powerbook 1.67Ghz with 1GB of RAM. Everytime I look in Activity Monitor I'm left with between 10-30 megs of free RAM. Is this normal? I wouldn't think so. The only programs I usually leave open are iCal, Mail, iChat, and sometimes Safari/iTunes. Is there some program to instantly free up RAM? Any input is appreciated.

Thanks.

Big Mac · Jun 23, 2005, 07:43 PM

Your concern is a common one, but there are a multiplicity of threads on OS X memory management. Search and you shall find.

bowwowman · Jun 23, 2005, 07:48 PM

I've only got 1gb in my B&W G4 and run many more ( & more demanding) apps than you listed, and I almost always have 2-300mb free. But what you really need to be concerned about is Pageouts.

Open Terminal.app, type in top -u, and look for line with page-ins & out on it. See what your numbers are. If Page-outs are anything but Ø, then you need more real ram.....

Safari is known to have serious memory leaks, which could be the culprit.
Try another browser and see what happens......

sieb · Jun 23, 2005, 08:03 PM

This is normal for Unix. The OS will release ram as needed by other apps. Its called memory management, unlike some OSs, *caugh* Windowz *caugh*......

msuper69 · Jun 23, 2005, 08:50 PM

Originally Posted by sieb

This is normal for Unix. The OS will release ram as needed by other apps. Its called memory management, unlike some OSs, *caugh* Windowz *caugh*......

..and the Classic Mac OS. What a nightmare of manual jury-rigging that was!

Chuckit · Jun 23, 2005, 09:18 PM

Originally Posted by sieb

This is normal for Unix. The OS will release ram as needed by other apps. Its called memory management, unlike some OSs, *caugh* Windowz *caugh*......

What? Since when does Windows not have memory management?

sniffer · Jun 23, 2005, 10:31 PM

Free ram space is wasted ram space. Available ram space is ram space that is free to be used. Available ram space doesn't have to be empty.. That's memory management under OS X.

mrurmil · Jun 24, 2005, 12:24 AM

Here is the output from top - u in terminal:

PhysMem: 95.5M wired, 439M active, 391M inactive, 926M used, 97.4M free
VM: 5.67G + 131M 43476(0) pageins, 675(0) pageouts

Big Mac · Jun 24, 2005, 12:59 AM

Nothing at all to worry about there, mrumril. Now if, in a short period of time, you were to see a lot of pageouts (or if pageouts outnumbered pageins), then free RAM would be a concern.

Kevin · Jun 24, 2005, 07:44 AM

Originally Posted by bowwowman

Safari is known to have serious memory leaks, which could be the culprit.
Try another browser and see what happens......

Older version did. Version 2 seamed to have gotten that taken care of.

Busemann · Jun 24, 2005, 08:26 AM

Originally Posted by KevinK

Older version did. Version 2 seamed to have gotten that taken care of.

Not really

viruscool · Jun 24, 2005, 08:50 AM

Here's my results from top -u

PhysMem: 97.2M wired, 238M active, 323M inactive, 659M used, 108M free
VM: 4.98G + 165M 307146(0) pageins, 59542(0) pageouts

Is this ok? Note that my comp has been up for 11 days.

proton · Jun 24, 2005, 08:57 AM

Originally Posted by bowwowman

I've only got 1gb in my B&W G4 and run many more ( & more demanding) apps than you listed, and I almost always have 2-300mb free. But what you really need to be concerned about is Pageouts.

Open Terminal.app, type in top -u, and look for line with page-ins & out on it. See what your numbers are. If Page-outs are anything but Ø, then you need more real ram.....

No! If pageouts/pageins are increasing rapidly and regularly then you need more RAM.

I've got 2.5GB of RAM and shortly after a reboot (a few hours) I've got 42959/2921 pagein/pageouts. After a few weeks of uptime, these numbers are in the millions. This is not a problem. This is by design.

Additionally, OS X will try and fill all your RAM, it's normal for it to operate with about 20MB free all the time. This is not a problem. This is by design.

In general, unless you actually have a problem, don't worry about memory statistics on Mac OS X, the operating system can handle its memory very well. The virtual memory system in a modern operating system is extremely complex, but in general you can just trust it's doing its job correctly.

- proton

proton · Jun 24, 2005, 08:58 AM

Here's my results from top -u

PhysMem: 97.2M wired, 238M active, 323M inactive, 659M used, 108M free
VM: 4.98G + 165M 307146(0) pageins, 59542(0) pageouts

Is this ok? Note that my comp has been up for 11 days.

That is fine. Absolutely nothing to worry about.

- proton

cybergoober · Jun 24, 2005, 09:02 AM

Ouch!

Code:
PhysMem:  98.4M wired,  272M active,  134M inactive,  505M used, 6.81M free
VM: 7.99G +  142M   1317550(0) pageins, 2241463(0) pageouts

More pageouts than pageins can't be good, right?
uptime is reporting (incorrectly) up 29 days...

G5 Dual 1.8 GHz -- 512 MB RAM -- Not my machine, so I can't just go out and buy RAM for it.

viruscool · Jun 24, 2005, 09:06 AM

Originally Posted by proton

That is fine. Absolutely nothing to worry about.

- proton

Thanks for the quick response.

chris v · Jun 24, 2005, 09:34 AM

Originally Posted by cybergoober

Ouch!

Code:
PhysMem:  98.4M wired,  272M active,  134M inactive,  505M used, 6.81M free
VM: 7.99G +  142M   1317550(0) pageins, 2241463(0) pageouts

More pageouts than pageins can't be good, right?

not necessarily. That just means inactive stuff has been sent to VM, but hasn't been called back up, as of yet.

Millennium · Jun 24, 2005, 09:37 AM

Originally Posted by cybergoober

Ouch!

Code:
PhysMem:  98.4M wired,  272M active,  134M inactive,  505M used, 6.81M free
VM: 7.99G +  142M   1317550(0) pageins, 2241463(0) pageouts

More pageouts than pageins can't be good, right?
uptime is reporting (incorrectly) up 29 days...

G5 Dual 1.8 GHz -- 512 MB RAM -- Not my machine, so I can't just go out and buy RAM for it.

If I recall correctly, top only reports the total number of pageins and pageouts in a given time period, not since boot, so having more pageouts than pageins may actually be a Good Thing. It depends on how you're using the system, but one way to get this situation would be by quitting RAM-intensive applications, in which case the system is merely cleaning out its virtual memory.

Ahem. To answer mrurmil's question: OSX manages memory in a very different way from OS9 and Windows, in that applications do not take up fixed amounts of RAM. This is why you can't just set the amount of RAM used by an app; the concept doesn't really apply. Applications will ordinarily take up as much RAM as they can -which may be more than they need- but RAM which isn't actually being used will be freed up by the OS for other apps as needed. It's a different way of doing things, but on the whole it tends to be more efficient. As such, there is no app to "instantly free up RAM" like the old Mac OS Purge, but there isn't a need for such an app either.