I was just offered the 10.4.6 Update by Software Update. I thought the PowerPC one was pretty large at 65.8MB, but I noticed that the Intel version is 163MB. Also of interest are these notes: If you use iSync, you should perform a full sync with your devices before installing this update. With the Mac OS X 10.4.6 system software update, PowerPC-based Macs will restart twice, instead of once, after the initial installation Here's the basic info: The 10.4.6 Update is recommended for all users and includes general operating system fixes, as well as specific fixes for the following applications and technologies: - login and authentication in a variety of network environments - file access and byte range locking with AFP file sharing - network access when using proxy server automatic configuration files - connecting to Cisco VPN servers using IP/Sec - using Bluetooth wireless devices - searching iWork '06 and Microsoft Office documents with Spotlight - saving Word documents automatically when using a network home directory - creating Automator workflows for iPhoto 6 - synchronizing contacts and calendars to .Mac and mobile phones - mounting and unmounting iDisk volumes - compatibility with third party applications and devices - previous standalone security updates For detailed information on this Update, please visit this website: http://www.info.apple.com/kbnum/n303411