Apple's Mac Pro Audio Update 1.0 for early 2009 Mac Pro models comes only with terse release notes, stating that the update "reduces processor utilization during audio activities such as playing or recording music." More information regarding installation steps is available on Apple's Web site. The update is available via Software Update and the Apple Support Downloads page. (Free, 1.64 MB)
Syslogd Overwhelming Your Computer?
If your Leopard (Mac OS X 10.5) system is unexpectedly sluggish, logging might be the culprit. Run Activity Monitor (Applications/Utilities/ folder), and click the CPU column twice to get it to show most to least activity. If syslogd is at the top of the list, there's a fix. Syslogd tracks informational messages produced by software and writes them to the asl.db, a file in your Unix /var/log/ directory. It's a known problem that syslogd can run amok. There's a fix: deleting the asl.db file.
Launch Terminal (from the same Utilities folder), and enter these commands exactly as written, entering your administrative password when prompted:
sudo launchctl stop com.apple.syslogd
sudo rm /var/log/asl.db
sudo launchctl start com.apple.syslogd
Your system should settle down to normal. For more information, follow the link.