lro seem to be off by default.
in Terminal:
If you do sudo sysctl -a | grep net.inet.tcp.lro you can see for your self.
To turn it on do sudo sysctl -w net.inet.tcp.lro=1
tso seem to be on by default:
sudo sysctl -a | grep net.inet.tcp.tso
To turn it off do sudo sysctl -w net.inet.tcp.tso=0
To have any sysctl setting stick between restarts create a file: /etc/sysctl.conf and add a row of text like
net.inet.tcp.tso=0