I think this is a pretty amusing tidbit. A few weeks ago I noticed a MySQL database taking a little more CPU than expected. Nothing dramatic. This is a small VM on a host running several and as the graph shows it doesn’t even break 25% capacity.
After about an hour I was able to reduce the CPU consumption considerably by updating, making sure indexes were optimal etc. etc. Nothing incredibly dramatic. Hardly a herculean task.
Now a week later I can clearly see the power consumption dropped a little bit on this particular host as a result of my optimization work.
Just goes to show, even if you run stuff in house and have extra computational power handy, it can add up.
1W of electricity @ $0.17 running 24 x 7 x 365 = $1.50/year. Literally a measurable improvement.