Apple has released MacBook Pro EFI Firmware Update 1.9, which addresses an issue we have covered extensively in which users experience frequent stalls/hangs, accompanied by the spinning beach ball progress indicator, under varying conditions (previously noted here). The problem appears to be hard drive-related, and occurs most frequently with the standard 320 GB 5400 RPM drive, but is also occurring with the 5400 500GB and 7200 500GB drives.
When this problem occurs, the hard drive becomes unresponsive for up to 30 seconds. During the stall, all applications will stall and or cease to properly function, but the mouse cursor can still be moved. CPU usage does not spike.
Apple says the update: “resolves a rare issue that may cause the system to freeze during startup or intermittently stall during operation, and it improves compatibility with external displays.”
Visit this page for a download of the update and important instructions for applying it.