7771 Views 10 Replies Latest reply: Dec 26, 2007 11:06 AM by Mark Delgrosso
I don't have an answer for you but am noticing the same thing. On leopard after one day I'm seeing active+wired ram used reach over 1GB with nothing open and Activity Monitor confirming nothing is hogging the memory. Even a logout and back in doesn't change it substantially. Even more troubling is the amount of Swap Used. After 24 hours I have over 1GB of swap used with 2GB allocated in /var/vm. The number of page outs have increased by a factor of 10000 over tiger resulting in an extraordinary amount of hard drive activity making the right wrist rest hotter than I've ever felt it along with sluggish performance while it's swapping
In tiger, even after 30+ days of uptime, my swap used never got above 80MB with almost zero page outs.
i was going to start a new thread about this, but decided to add to this one instead. i've got a 24" aluminum imac and did an "archive and install" option for leopard about a week ago. cold booting tiger on this machine would average about 275megs of RAM being used. switching over to leopard has quadrupled that to about 1.1gigs of RAM. i find this incredibly unsettling. i took a look at activity monitor and with "all processes" showing, i've noticed that the "kernal_task" is using approximately 430megs (before, it wouldn't reach past 200). the "massstorage" task is taking up a whopping 115megs! considering that it's not using any CPU time. and "image capture extension" is taking up another 110megs!!! am i missing something here? i have three external harddrives, each connected via a different port (usb2, firewire400, firewire 800). any help on this would be appreciated. on my coreduo macbook is takes 388megs to boot up, which is also (roughly) twice the amount from tiger. any ideas or help would be great.
okay, i did some experimenting and realized that if i renamed the firewire 400 external drive from "media" to "other" and renamed one of the root folders from "images" to "pictures" both the "massstorage" and "image capture extension" processes both wouldn't activate. so, i'm guessing that leopard takes any external device with a folder labeled "images" as some sort of media card and launches both of those processes to help iphoto with the import process. so it saved me about 210 megs of RAM, but leopard is still using up quite a bit. hope this helps someone.
I have the same problem. I have 2GB ram. After a restart memory usage keeps growing even though I don't have much more than Mail, Terminal, Safari and TextMate running and after about a day the swap starts to grow (even though activity monitor sometimes shows maybe 200MB free and 500MB inactive). Give it a few more hours and I now have 800MB swap used and 1G page ins.
Even if I quit every app except activity monitor and relaunch the finder I have >200MB wired memory, >600MB active and >300MB swap used. The single largest process at that point is kernel_task at 130MB (real memory), followed by WindowServer at 40MB.
Interesting, I'm noticing the same problem on my Mac Pro. I'm watching my RAM usage with iStat Menus in my menu bar, so I always have an eye on it. Initially after booting only a little amount of memory is used, but for example last weekend I noticed that over the course of a day memory usage creeped up without me actually doing much, just mainly using Firefox, Mail, Adium, and Finder. Even after closing all open applications the hogged RAM would not be released again, only a reboot accomplishes that. Seems like Leopard may have some memory leaks, with Tiger I never noticed such a behaviour.
This is NOT a problem - at least not necessarily.
It's been discussed here and in other places many times.
What you're seeing is Mac OS X's caching at work.
The best way to think of it is "unused RAM = wasted RAM". Really.
What's happening is that when you boot your system you have the maximum amount of memory available. As you work, launch applications, open documents, etc., the OS keeps much of that data in memory, even after the document has been saved to disk, and even after the application has quit.
Why does it do this? Because it (and probably even you) don't know when you'll need that data again.
It may be that you close a word processor document, only to realize you forgot to add a closing paragraph. Maybe you quit Mail.app then realized you need to send one more email.
Whatever the reason, the fact that Mac OS X still has much of this data in cache means that you can reopen/relaunch documents and applications much, much faster.
To prove this theory, get a stopwatch. Time how long it takes to launch an application (any application) immediately after boot. Then quit the app and time it again. You'll find the second launch much, much faster - that is thanks to the cache. Much of the data is being restored from the cache rather than read from disk.
This can't go on indefinitely, of course, so the OS keeps track of how much memory is unused and how much each application is asking for. As soon as any app asks for more memory than is available the OS clears out the oldest cache items.
The only time this is a problem is when you need more active memory than you have in your machine. Maybe you have Final Cut Pro processing a 5 GB movie while you're downloading from the web, getting email while listening to iTunes. If you don't have enough memory for active processes then the OS will slow down significantly as it pages to disk, but at that point the cache isn't an issue anyway - you simply need more memory.
The best gauge of your memory usage is not Menu Meters, but either top or Activity Monitor.app, both of which will show the breakdown of memory usage.
For example, here's an 8GB machine that is using memory very effectively:
<pre class=command>PhysMem: 820M wired, 4.74G active, 2.17G inactive, 7.71G used, 343M free</pre>
You might worry that the 343M free is too low, but it isn't. Not when you consider:
9:29 up 306 days, 9:30, 1 user, load averages: 0.67 0.54 0.50
where you can see the machine has been running for 10 months. (Sure, this indicates that the machine is running Tiger not Leopard, but the same principles hold true - much of the 7.7GB of 'used' memory is cached data.).
In fact, just over half the actual memory in the machine is actively being used by processes - that's the '4.74G used' figure. Over 2GB in memory is sitting around holding idle processes and cache data.
So the number to watch (and worry about) is either the 'active memory' (which needs to be less than your total RAM), or the sum of 'free' and 'inactive' (which indicates how much headroom you have before you run out).
Let the OS do its cache thing. You'd really miss it if it didn't have it.