When GarageBand cannot read or write data fast enough to keep up with the playing song, you may see one of the following messages:
"System Overload"
"The hard disk is not fast enough to deliver all audio data in time. Try muting some tracks."
"Disk is too slow."
"Result code = -61"

Here are some tips to help avoid these performance issues:

• Make sure you are using the most recent version of GarageBand. Updates can be downloaded using Software Update or from the GarageBand Download page.

• FileVault can cause reading data from your home directory to be significantly slower. If you wish to leave FileVault on, be sure to keep your songs outside of your home directory. FileVault options are available in Security preferences.

• Quit other open applications.

• Optimize for Better Performance.

1. From the GarageBand menu, choose Preferences.
2. Click the Audio/MIDI button.
3. In the "Optimize for" section, click "Better performance" to select that option. With GarageBand 1.0.1 and later, click "Maximum number of simultaneous tracks." Selecting this option may cause some latency.

• Depending on the speed of your computer's microprocessor and the speed of your hard drive, you may have too many tracks in your song. Try deleting or combining tracks where possible.

• Choose fewer tracks and fewer voices per instrument.

1. From the GarageBand menu, choose Preferences.
2. Click the Advanced button.
3. From both the Real Instrument Tracks and Software Instrument Tracks pop-up menus, choose lower settings.
4. From the Voices per instrument pop-up menu, choose a lower setting .

• Don't open a song directly from a CD or DVD. Copy it to the hard disk first.

• Quit and reopen GarageBand.

Tip: To test basic performance in GarageBand, try playing demo songs with fewer tracks such as "Glide". Some of the GarageBand demo songs on the iLife DVD are very processor intensive and may not play on slower computers.
http://docs.info.apple.com/article.html?artnum=93618

MACinations October 04