msk doesn't work under 10-amd64 but does on i386

[John]

Hello list,

I have a notebook machine that I've converted to act as a small 
low-power server because its hinges have worn out. It's an atom samsung 
notebook. The cpu identifies as:

Intel(R) Atom(TM) CPU N450   @ 1.66GHz

it is 64-bit capable:

Extended feature flags set 1 (CPUID.80000001H:EDX): 20000000
EM64T     Intel Extended Memory 64 Technology

so I installed the 10.1-R amd64 memstick. All goes well, it reboots, I 
ssh into it and things are fine for a few minnutes but then I get the 
following at the console:

mmsk0: watchdog timeout

and I lose the connection, can't ping anything including its gateway 
from the device. A reboot will restore connectivity for a short period 
but the same thing happens again. I tried with the latest 11 snapshot 
and also tried with 10.0-R amd64 and get the same result. Then I tried 
with the 10.1-R i386 (in other words, 32 bit) memstick and everything 
works fine.

Why the difference?
-- 
John