Apple Macintosh Performa 6400 Series - Manual (Page 65)

Using application programs designed for the PowerPC microprocessor
Your Macintosh is compatible with most application programs intended for
use with Macintosh computers, but certain programs are designed especially
for computers that have the PowerPC microprocessor. (These programs are
sometimes called “native” applications.) These programs take best advantage
of your computer’s speed.
Special memory requirements
Some native applications may be slightly larger than other programs and may
take up more memory. If you find that you are running out of memory when
you use one of these programs, you can use space on your computer’s hard
disk as additional memory, which is called virtual memory. For instructions
on how to use virtual memory, see the “Memory” topic of Macintosh Guide,
available in the Guide (h) menu.
You can also add more memory to your computer, as described in
Appendix B, “Installing Additional Memory.”
Using older Macintosh programs
If you experience problems using an older Macintosh program, it may be
incompatible with your Macintosh. You may be able to use your older
program if you turn off Modern Memory Manager. To do this, pull down the
Apple (K) menu, open the Control Panels submenu, and select the Memory
control panel. Then turn off Modern Memory Manager.
65 Using Programs and Backing Up Disks