Macintosh Memory Usage

If you are using System 7.5 or greater, the Apple Guide contains most or all of the information on this page. To use the Apple Guide, select it from the Help menu (The one with the question mark icon). You should also try opening your Memory control panel and enabling Balloon Help.

What is Memory?

First off, let me state that when ever I speak of "Memory", I mean RAM (Random Access Memory), not Disk Space. A lot of people confuse the two. In many respects the two are similar. Both are measured in terms of Bytes, KiloBytes, or MegaBytes (GigaBytes, TeraBytes, etc.) If you get down to it, they both amount to a bunch of single "cells" that can either contain a "1" or a "0". However, in the ways that we care about here, they are different.

One way to look at the difference is to imagine your Mac as a brain. Think of RAM as the part of your brain that's thinking right now. And Disk Space as all of those things that you could think about if you choose to.

An important difference between RAM and Disk Space is that RAM is much faster to access. (If you're already think about something, then you don't have to think about thinking about it ;-) This becomes important when we start i exploring Virtual Memory and RAM Disk.

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Memory Problems

When any application is launched, it asks for a certain amount of RAM to be set aside for it to use. If, for some reason, the application needs more memory than that, it will do one of three things:
  1. Not do what you want it to
  2. Quit or Crash
  3. Warn you that it needs more memory
The Application is out of memory space. There are two things that can be done at this point: Give it more memory or reduce it's need for more memory.

Adjusting Application Memory

If you need to increase the memory allocation for an Application, you can do this fairly easily. Prior to doing this, it is a good idea to take a look at your typical Memory usage on your Mac by selcting "About This Macintosh".

Get Info

  1. Quit the application

  2. Select the Application's Icon (Be careful not to select an alias of it)

  3. Choose "Get Info..." from the File Menu.

  4. Adjust the number in the field marked "Preferred Size" up by 30-50%.

  5. Close the Get Info window and launch the application.

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How Much Memory is being used?

Let's take a look at how much Memory is being used by the various applications that are currently running:

Open up your "normal" array of Applications and then,

About This Mac

Select "About This Macintosh..." while in the Finder.
Try turning on "Balloon Help" from the Help menu.

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Using Less Memory

Just as with economics and recycling, the best way to avoid memory problems is to use memory wisely.

Often you can get by with less memory than you currently are. Now that you've checked to see how much memory each application is using, you can use this information to optimize your memory usage.

Some Guidlines:

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Buying More Memory

In today's environment, there may come a time when juggling memory from one application to another no longer works. At this point, you should add more memory to your Mac.

Right now, Memory is cheap and it is one of the most important things that you can add to your Mac. Check out the Memory Pricing Guide for info.

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Virtual Memory

Virtual Memory is a method of sacrificing disk space in order to give your Macintosh more RAM. To do this, your Mac blocks out however much Disk Space that you set Virtual Memory for. Then it tries to keep what ever you are currently working on in actual RAM and "swaps" things that you don't currently need to a large block of Disk Space until you need it again.

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RAM Disk

A RAM Disk is kind of the opposite of Virtual Memory. When you set up a RAM Disk, you are asking your Mac to set aside a part of its RAM for you to use as Disk Space. There are two main reasons to use a RAM Disk: Important Be aware that something that you save to a RAM Disk is *not* saved to your Hard Drive. If your Mac crashes and you have anything in a RAM Disk, it is *gone*.

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Last Modified - Feb-11-1997