Hi,

I'm not saying this is your problem, but a few years ago I had a VP6  
that worked in single CPU mode but not dual with NetBSD 1.6.   
Eventually, after having it lock up periodically, I gave up and ran  
it as a single CPU machine.  That lasted a couple of months before  
the CPU0 socket failed entirely and the machine stopped booting at all.

No smoke.  No noise.  The board/cpu was just plain bad, and there was  
no indication before it let go for good that this was the case.

Byron