Big time RAM usage / question about OS X and application RAM usage

[SteveC]

Hey all.

I recently upgraded my new iMac G5 to 1GB of RAM.

Is anyone here familiar with the way OS X uses RAM? Here's why I ask...

Just a few minutes ago, I had about 5 apps open (Adium, Acquisition, iChat, Safari, and iTunes), and I had about 700MB of RAM free. I opened Entourage to check my e-mail, and my available RAM went down to 42MB free. Does Entourage use 658MB of RAM? lol

What is more weird: After quitting Entourage, my free RAM only went up to about 80MB. Activity Monitor now says I am using 971MB of RAM and have 52MB free. The only apps I have open are Safari, Activity Monitor, Adium, and Acquisition.

When I only had 512MB of RAM, I had high RAM pageout numbers, and those numbers have shrunk considerably now that I have 1GB, so I *believe* the extra RAM is helping. But I still have SOME pageouts occurring, and I have no idea why, with so much RAM in my system. I just have no idea why my computer is using 900MB of RAM now that I have 1GB total, and it was only using 400MB when I had 512 total.

Why is so much RAM being used now? I was thinking I could expect to have 300-500 MB free most of the time.

Edit: By the way, do my Wired, Active, Inactive, and Used numbers mean anything helpful? I have 87 wired, 226 active, 672 inactive, and 985 used now, with 38 free.

 

[jestershinra]

Activity Monitor is annoying in its assessment and display of available RAM. Essentially, your free RAM is "free" + "inactive". I don't know what the difference is between these two, but I doubt Entourage uses that much RAM. It doesn't for me.

 

[smokeyrabbit]

Old Link Apple Techinical article Another one One More

Don't worry about how much free memory you have. If you are slowing down because of VM paging then get more memory. Hopefully after reading the above pages you will learn that OS X keeps apps in memory even after they quit in order to speed up subsequent launches.

 

[smokeyrabbit]

When I only had 512MB of RAM, I had high RAM pageout numbers, and those numbers have shrunk considerably now that I have 1GB, so I *believe* the extra RAM is helping. But I still have SOME pageouts occurring, and I have no idea why, with so much RAM in my system. I just have no idea why my computer is using 900MB of RAM now that I have 1GB total, and it was only using 400MB when I had 512 total.

Yes, this is how OS X works with memory management

 

[SteveC]

Old Link Apple Techinical article Another one One More

Don't worry about how much free memory you have. If you are slowing down because of VM paging then get more memory. Hopefully after reading the above pages you will learn that OS X keeps apps in memory even after they quit in order to speed up subsequent launches.

Ahh, cool. Thanks for the very helpful info. in your post and in those links.

Based on what I learned from the articles, the only ways to get back up to a large amount of "free" RAM are to restart or shut down and turn the computer back on. But the "free" number is not a concern since previously used apps count against that.

Good stuff. I feel happier about my RAM purchase now. I was wondering if it did any good lol. Now I know how it works.

Thanks!