Improving Network Performance on Mac OS X

The default Mac OS X 10.4 has a default configuration for delayed ACK that made some of my network operations unbearably slow, most notably Samba. This note on Mac OS X Hints fixed things for me, improving transfer speeds noticeably. The short version: add net.inet.tcp.delayed_ack=0 to the end of /etc/sysctl.conf and reboot.