FreeBSD 9.1 freezes randomly on G5

[Michael Copeland]

Those of you that saw my posts from a few months ago regarding the same
machine as the one in question, I had the same issues he is having. The
fans would go full blast, the system would hang without any form of console
message. It all stopped when I ran the pmu/smu/fan script that some people
in this mailing list have used. So I'm thinking it is definitely an issue
with the smu driver or the smu itself on this machine.