>The Tape server, an SGI Indy, has a Phobos G130 10/100 card.  The Cisco
>it's connected to was set to auto-detect, the card was forced 100Full.
>So, changing the cisco to force 100Full fixed it.  The interesting thing
>is, it only slowed down this one machine.  It turns out that when I did a
>huge rack move, the old ethernet line was set correctly, but after the
>move the new one wasn't.  So, now all is well, the Sun is better than
>ever, and cross-my-fingers, everything is working well.

I've seen this sort of thing a number of times, especially with Suns. 
Our Bayfleet switches don't seem to play auto-detect / auto-negotiate
well with our Suns, so we force everything to 100fdx.  On occasion a
switch port decides on its own to change to hdx, and we a slowdown in
traffic to/from *some* other machines on the same switch.  Maybe it's
weirdness in the switch, maybe load patterns are involved.