System becomes unresponsive, hard reboot required (multiple Macs)

Question

For the last couple of weeks I have been encountering unresponsive systems on several Macs, each time with the same symptoms:
Spinning beachball in all running apps
Spinning beachball for all menu items
Unable to launch, quit or force quit apps
Mousing and window switching still works
Each time the only way to recover is a hard reboot. There seems to be no mention of any problems in the system logs, I get the impression that the system is hanging before being able to report anything.
I have this problem on three Macs so far, a 2x2.3Ghz PowerMac G5, a 2x2.0Ghz PowerMac G5 and my iMac G5 2.0Ghz at home. All systems are running 10.4.10.
Has anyone else had this problem? Any solutions?
Edit: I have already repaired permissions, emptied caches, run scheduled maintenance, sacrificed chickens, etc.
Message was edited by: Si Buckmaster

Answer 1

I don't think it's a lack of memory, 2.5Gb, 2.0Gb and 1,0Gb respectively.
My G5 at work (2.5Ghz) and my iMac at home have very similar setups as far as installed apps and settings, however the third Mac at work has very little in common with the other two. OTOH the only non-Apple software all three Macs have in common is Adobe Creative Suite (2xCS3, 1xCS1), Quicksilver and Growl.
I figure it must be something system related because a user level app shouldn't take out all the others like that, I was hoping to find that I wasn't the only person experiencing these problems!
I have the terminal open with my session on my work Mac, but I had closed the window before it last beachballed and it wouldn't open a new one. Even if the window had been open I doubt it would have responded.
I will try to SSH into whichever Mac beachballs next to see if it responds, but I know it happened at home once while I was streaming a film from the iMac and the film immediately stopped. At first I suspected it was network related because the Airport menu item always seemed to be the first thing to beachball at home, but all the network connections are wired at the office.