> >
> > what cards? 3c509 gives over 900kB/s
> 
> On the integrated le interfaces (AMD79c960), we cards (Western
> Digital) and ec cards (Etherlink II).  I've verified it's not the
> switch/hub, as other cards (de and tlp cards) as well as my sparcs run at
> close to 980K/s.
really strange except we which are slow, but 3coms gives speeds near the
maximum.. at least on linux on 486... 
could you set ISA clock? try increasing from default 7.somethingMhz to
PCI/3  in BIOS