from openbsd's "man ti" (which is appears as).
           o   The Netgear GA620 Gigabit Ethernet adapter (1000baseSX)

Alteon chipset used by many cards.  Mine is a  GA620.

I use two with two machines (crossover fiber).  REALLY fast,
nice to have no electrical connections between these two systems
(ones on a UPS, ones on an isolater on the stereo and ground loops
are a pain).

I've ftp'd at nearly 100MB/s.
Again, 2.  

A third would mean buying over priced hubs.

Quoting Chuck Yerkes (chuck+nbsd@2003.snew.com):
> I've got a netgear one, but not in the NetBSD box.
> A GAsomething (GA102?).  Works wonderfully with
> Linux, OpenBSD and FreeBSD.  I'd expect the same
> from NetBSD.
> 
> Quoting Michael Graff (explorer@flame.org):
> > Kevin Sullivan <ksulliva@psc.edu> writes:
> > 
> > > Any suggestions?
> > 
> > I think we're using some Netgear one that seems to be based on an
> > Intel chipset.  I can find out more if that isn't sufficient.