Freeze due to performance_cx_lowest=LOW

Hi,

A while ago I installed CURRENT on my new home PC and noticed that
the system would hang hard at the boot time soon after setting
cx_lowest to C3 according to the LOW setting in /etc/defaults/rc.conf.
The last message on the console was each time: Mounting NFS file
systems:.  Setting performance_cx_lowest to HIGH made the problem
go away.

Now I've just tried again to return performance_cx_lowest to its
modern default setting in a fresh CURRENT and found that the bug
is still there.  Is it due to my ACPI HW being broken?  I'll be
glad to show relevant debug output from my ACPI if told how to get
it.  Thanks.

-- 
Yar