It's cool to be green (plug power\temperature reduction)

[Confusticated]

The thermal output\power consumption of the semiconductors running at 1000Mbps is considerably greater than that running at 100Mbps.
If you are in the situation where an existing Gigabit Switch is most convenient, but 100Mbps is quite satisfactory....

Code:

apt-get install ethtool

File /etc/rc.local

Code:

...
# knock back negotiation on eth0 to 100Mbps Full Duplex or less
ethtool -s eth0 advertise 0x00F
...

The temperature reduction is significant

[Ralph Houston]

Interesting notion - but when I checked, my eth0 (not in use) was already set to 10Mbps, and eth1 (in use on 8MBps line) showed 100Mbps - so something has already set these to sensible values