Clock stalls on Sabertooth 990FX

[Joe Schaefer]

Brand new machine with a Phenom II X6 1100T and under chronic load
the clock will stop running periodically until the machine eventually completely
freezes.  Note: during these stalls the kernel is still running, the
machine is still
mostly responsive, it's just that the clock is frozen in time.

I've disabled Turbo mode in the bios and toyed with just about every
other setting but nothing seems to resolve this problem.  Based on the behavior
of the machine (just making buildworld will eventually kill it, upping
the -j flag
just kills it faster), I'm guessing it has something to do with the
Digi+ VRM features
but again nothing I've tried modifying in the bios seems to help.

I've tried both 8.2-RELEASE and FreeBSD 9 (head).  Running head now with
a dtrace enabled kernel.

Suggestions?