No NFS problems. NFS hangs often. We have to run a buggy half-duplex low bandwidth de4x5 driver on them as the tulip driver is even worse. So the answer is that Linux NFS stability depends greatly on what sort of network cards you're running.
New tulips are bad.
It's pretty funny that Compaq actually market these things as Linux servers - pah. I can tweak the OS too - just don't know what to change.