I have just powered up my old 11/750 to see where network performance
stands today :-) It have a DEUNA as nic card; good old slow one.

Some quick tests shows this result. It is done by ftp'ing the kernel 
to and from a sun machine a couple of times. There are very little
variance in the numbers when doing it multiple times:

1.4 GENERIC:
        get /vmunix /dev/null: 152 KB/s
        put /netbsd /dev/null: 62 KB/s

1.5 GENERIC:
        get /vmunix /dev/null: 112 KB/s
        put /netbsd /dev/null: 76 KB/s

1.5S GENERIC (unoptimized in4_cksum):
        get /vmunix /dev/null: 117 KB/s
        put /netbsd /dev/null: 90 KB/s

1.5T GENERIC (optimized in4_cksum):
        get /vmunix /dev/null: 136 KB/s
        put /netbsd /dev/null: 90 KB/s

1.5T tailored, without IPv6:
	get /vmunix /dev/null: 145 KB/s
	put /netbsd /dev/null: 93 KB/s


This shows that TCP sending have increased significantly (50%) from 1.4
which was the fastest release before. The receive speed has slowed down
a bit, but also note that if a tailored 11/750 kernel without VLAN, IPv6
and those bits is used it gets even faster.

Separate note: If you are using a 11/750, compile all binaries static. 
It takes an annoying time for the dynamic linked binaries to start :-)

-- Ragge