Chant the matra with me:
  Autoselect is bad, I will always force my interfaces to what
  I want.

Just sing thing in the shower, on the can, as you drive to work.

Quoting Peter Eisch (peter@boku.net):
> 
> It was ultimately an issue of duplex.  The netbsd nics were set to
> autoselect, as was the switch.  Switch said "Full" and I have no idea what
> the nics were other than how ifconfig reports autoselect.  I ultimately
> hard-coded the whole collection of ports and nics to 100/Full.
> 
> It was interesting that the 3c905s/ex didn't bring up the FlowControl on the
> switch as enabled while the i8255x/fxp's did.  So I'm back in my happy place
> again.
> 
> I'm painfully aware of the issue with cisco cat's, but for some reason that
> hadn't occurred to me here.
> 
> Thanks all,
> 
> peter