bruce, it's true, there are several facilities that will "squish" the inactive pages.

in the shell, a find or du over a large section of the filesystem will peel off "expired" inactive pages.

seems like large disk cache i/o triggers virtual memory management of "expired" inactive pages.

Wouldn't this account for the incredible disparities of OSX performance perception/actual results where some like myself are very happy with OSX on a G3 400 and others complain about constant beachballs wih DP towers? Maybe they have little or no free RAM left and are actually running OSX from disk virtual memory! I have seen VPC gobble up +400MB of inactive RAM in use and release less than 100MB when quit. Relaunch again and your +1GB RAM is gone.

I always closely monitor free RAM and quit idle apps or scan the volume as needed to keep performance consistently high. I'm serious when I say I hardly ever see any beachballs.

I have seen it written many places that one does not need to quit idle apps on OSX. Are you saying that this is incorrect?

With my modest system, I can see RAM useage grow with SOME apps such as VPC (maybe an extreme example) simply sitting idle consuming huge amounts of free RAM. If I launch PhotoShop and use it, I can observe 1GB of RAM disappear because VPC is sitting idle. Play with MemoryStick, it takes up little desktop real estate and is VERY revealing about on-going all-important RAM useage. The promise of memory management in OSX and the reality (as least as of 10.1.5) are not the same apparently.

perception is a real oddity, influenced by mythology, hearsay and uncorroborated experiences. add to that the lack of knowledge of phenomena you find sprinkled around and it seems to me that a lot of people philosophically need a change of diapers.

you don't need to quit idle apps, but it sure affects memory management which improves overall performance over time; if you have a picture of memory and you can alter it by dispensing with idle apps, you are proactively managing your performance. idle they may be, but they have their fingers in resources that need managing by the kernel.

Merv,

Another example of cutting through the voodoo, I found was the simple concept that with VPC, the smaller the virtual hard drive image size, the faster Windows performed regardless of what version used. My 98SE flew when the drive was stripped down to an essential 350MB and was a pig when loaded with apps and became a 1.5GB drive image. Every app added cut speed just a little bit. The idea seemed rudimentary to me, after all doesn't a 300MB file take longer to open, scroll or alter than a 3MB file, which all a Windows OS is to the Mac, a file folder to open and search through? I thought, why not have multiple copies of a VPC Windows OS, each tailored to only the essential app needed for each drive image for the purpose of speed.

Well, you would think I committed heresy when I posted the concept at the Connectix VPC forum. One of their head engineers replied it was "one of the craziest ideas" he had heard of. I didn't bother to reply and suggest he simply try it and see for himself. Yet there are posters there who can't get Windows XP to even launch IE in VPC in less than 5 minutes on their DP towers, while I get IE pages to load in XP at about dial-up speed (via dsl) with my G3 400 and minimalist XP drive image. Logically, there has to be something going on to account for such huge performance extremes.

Now over at MacWindows a concept of separating the OS from applications (via networking) in Windows VPC was tested and is being proposed to create smaller multiple drive image files to use less disk i/o to compensate for the terrible speed hit that occurred with VPC in OS10.2.1.

hmm, very interesting. and i don't think a bit of it sounds crazy, except from a management overhead point of view. but, thanks for pioneering. let us know what 'develops'.

Amazing
 

The memory arrived and I installed it this afternoon. There is a truly remarkable difference in how responsive the machine simply feels. Here are the stats:

That's after working with several M$ memory hog apps for a few hours! As well as Mozilla.