Add these to /etc/sysctl.conf and reboot.
kern.ipc.maxsockbuf=16777216
net.inet.tcp.rfc1323=1
net.inet.tcp.sendbuf_max=16777216Here are some other new settings in 7.0 to know about. Defaults for these should be fine.
net.inet.tcp.recvbuf_max=16777216
net.inet.tcp.sendbuf_auto=1 # Send buffer autotuning enabled by defaultSome additional information on NetBSD tuning can be found here.
net.inet.tcp.sendbuf_inc=8192 # step size
net.inet.tcp.recvbuf_auto=1 # enabled
net.inet.tcp.recvbuf_inc=16384 # step size
Note: FreeBSD versions before 4.10 don't have SACK implemented, which limits its throughput considerably compared to other operating systems. You should upgrade to 4.10 or higher.