Such a G4 would also be a nice bsd or linux shell system for a small number of users. I'm between local shell hosts, but my most recent such machine was a 1.4GHz Pentium M with 768MB of memory and a 250GB spinning disk. That machine received an upgrade to 1.5GB of memory pretty recently.
For that kind of task, not much other than that the machine is relatively small and quiet matters.
Xgrid cluster would be really interesting use for such a group of machines, the biggest challenge is that the G4 mini only has 10/100 networking, which I seem to recall back in the day meant that your money was usually better spent on fewer bigger systems to do your task, though it would sort of depend on how the network is used by your particular task. (i.e. if it's really a distribution method for tasks that take a long time to run, the way SETI et al work, or if it needs really intense network access, which I'm told a lot of xgrid tasks like video rendering and distributed xcode compiles require.)
It would be neat to look at either way.
For that kind of task, not much other than that the machine is relatively small and quiet matters.
Xgrid cluster would be really interesting use for such a group of machines, the biggest challenge is that the G4 mini only has 10/100 networking, which I seem to recall back in the day meant that your money was usually better spent on fewer bigger systems to do your task, though it would sort of depend on how the network is used by your particular task. (i.e. if it's really a distribution method for tasks that take a long time to run, the way SETI et al work, or if it needs really intense network access, which I'm told a lot of xgrid tasks like video rendering and distributed xcode compiles require.)
It would be neat to look at either way.