Power Macintosh 7500/8500: About Virtual Memory

TOPIC

This information about Virtual Memory is a part of the Power Macintosh 7500/8500 ReadMe file.

DISCUSSION

Virtual memory (VM) is a feature of the Mac OS that lets you use part of your hard disk as additional memory. If you are using an application program designed especially for Power Macintosh computers (often called a "native" application program), turning on virtual memory may help you avoid running out of memory.

Your computer comes with virtual memory turned on. With virtual memory turned on, a Power Macintosh program uses less memory than when virtual memory is turned off. If you check the program's Get Info box before and after turning on virtual memory, you'll see that the numbers in the Memory Requirements box change. That is because turning on virtual memory allows the program to use memory more efficiently.

If you notice performance problems (such as your computer's responses seeming unusually slow) using certain application programs, you may want to turn off virtual memory. For information on how to turn virtual memory on and off, choose Macintosh Guide from the Guide (question mark) menu, and click the Memory topic area. Then click "How do I use hard disk space as memory?" and "How do I manage Power Macintosh memory?"

For best performance, try setting virtual memory to no more than 150% of the memory (RAM) installed in your computer, or no more than 50% of your currently available hard drive space, whichever number is lower. For example, if your computer has 16 MB of RAM and your hard drive has 50 MB of available space, set virtual memory to a maximum of 24 MB (this is 150% of your 16 MB of RAM, and less than 50% of the available space on your hard drive).

To improve performance, you can also add memory (RAM) to your computer. See the user's manual that came with your computer for more information.

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