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evoLver · Sep 3, 2009, 01:19 PM

Hi. Using my 2.2GHz with 10.5.7, and not doing anything differently than I've ever done, my system is suddenly using over 3 GB RAM and then peaking at 3.90GB (out of 4) and then applications start freezing.

It first happened when using Ableton Live. I had Safari open as well. So this time I used Activity Monitor to watch it and Live did fine, stayed about 2.5G. I opened Safari and it kicked up to 2.7G. So I thought all was cool.

Then I opened Word, and then Toast to burn a DVD and forgot to check the activity monitor. Then the DVD burn failed. I closed all aps and the used RAM stayed at 3.90. So i restarted.

EDIT: Weird. Used RAM shows at 800MB with Safari open. When I checked earlier, after coming out of sleep mode, used RAM was 2.2GB with just Safari open.

evoLver · Sep 3, 2009, 01:46 PM

damn. Now I'm running my Live set, Safari with a flash player and Word and it's all staying below 2G used RAM. Makes no sense.

mduell · Sep 3, 2009, 06:19 PM

Applications freezing and disks failing to burn is probably unrelated to memory usage. Non-free memory usually isn't something to worry about. The OS uses otherwise-unused memory to cache files.

chabig · Sep 3, 2009, 06:29 PM

Originally Posted by evoLver

damn. Now I'm running my Live set, Safari with a flash player and Word and it's all staying below 2G used RAM. Makes no sense.

The computer will use as much RAM as it needs, all the way up to the max. There is nothing you should worry about, unless you think you might have a physical problem with your RAM chips, in which case you should run a hardware test.

evoLver · Sep 4, 2009, 02:59 AM

Well, the only thing is that this is a new development (computer using all 4 gigs of RAM). And it was the first time Ableton Live crashed on me without being able recover the work. And the message it gave was " There is not enough memory available. Please save now and quit".

chabig · Sep 4, 2009, 05:07 AM

That is very strange. It sounds like an Abelton problem, because the OS gives 32 bit apps as much memory as it needs up to a max of 4GB per appication, I think. Only 64 bit apps can use more than 4GB.

P · Sep 4, 2009, 05:12 AM

This should be stickied somewhere:

Mac OS X, like any modern OS, divides RAM into four categories: Wired, Active, Inactive and Free. Wired means stuff that should never be paged out to the HD (like important parts of the kernel), Active means stuff in current use that ideally shouldn't be paged out as it will likely cause a page fault in the future, Inactive means stuff that can be paged out at any time, as it is unlikely to be used again, and Free is memory that is available for loading more stuff into directly.

Ideally, Free should be zero at all time, because Free is wasted RAM. In practice it doesn't work that way, because you don't want to page out when you need RAM in an emergency, but Free being a low number is a Good Thing. It's when Free+Inactive is a low number that you have a problem, because then there isn't a lot of RAM that the OS can use. Pretty soon, it will have to page out Active stuff, which will cause a pagefault in the long run.

So: Ignore the Inactive part of your memory usage, and look at Active+Wired. If that grows without bounds, then you have a memory leak or similar. If it's just Inactive going up, don't worry about it, your problem is somewhere else.