Dr. Mac's OS X Tip-of-the-Day  

Face it - Mac OS X loves RAM. The more you have, the happier OS X is. And the more you demand of your Mac (I've got 13 applications running and, according to Process Viewer, 76 active processes right this second), the more more RAM will speed things up.

With Mac OS 9, when you ran short of RAM, your Mac would scold you and tell you there wasn't enough of the stuff to do whatever it was you were trying to do-usually launch a program.

In Mac OS X, memory management is a whole new ball of wax. The good old bar graph from About this Mac/Computer in the Apple menu is gone. Which is no big deal, because for the most part, knowing how much RAM individual applications are consuming in Mac OS X is useless.

In a nutshell, Mac OS X tricks every program into thinking it has unlimited RAM available to it regardless of how much RAM you actually have or how many programs you actually have open. Chalk it up to Mac OS X's advanced memory management system.

That is why Mac OS X can run lots of applications at once, even with only 128 or 256MB of RAM. It's also why applications don't run out of memory anymore and why Mac OS X never squawks about not having enough RAM.

Unfortunately, all that trickery has a price, and since you actually only have so much real RAM, at some point your Mac will start to slow down, because all the real RAM is being used. When this happens your Mac resorts to trickery to move some less-frequently used code fragments from RAM to your hard disk. This is called "swapping," or, more precisely, a "pageout".

Think of swapping as akin to Mac OS 9's virtual memory on amphetamines. But in Mac OS X, when all the real RAM is in use, pageouts will slow your Mac down, big time.

Which is a long way of saying that if you want to know how often you're paging out, get the first-ever two-time Freeware Friday honoree, MemoryStick, now up to version 1.1.

MemoryStick, which was my second Freeware Friday pick way back in February, does one thing Ñdisplay's a small window with a graphical display of your physical RAM usage. This tells you whether you have enough RAM to avoid pageouts. The more pageouts you have, the slower Mac OS X runs.

The latest version (1.1) adds a swap file indicator, a Dock icon with a working RAM graph, and user-configurable display colors. And the best feature, still, is the "Signal Pageouts" alarm. Turn it on, then listenÑthe more your Mac beeps the more you need more RAM.

Kudos to MemoryStick author Matt Neuburg. The program is elegant and does what it's supposed to do for free. What more could you ask for?

To discuss this tip (or anything you like) in Dr. Mac's OSXFAQ Forum, click here:

Bob LeVitus is a leading authority on Mac OS and the author of 38 books, including Mac OS X For Dummies and The Little iTunes Book.