> but what exactly would be a reason for putting a power saving CPU in something that's plugged into the wall?
Devil's advocate, but I imagine it'd do huge things to the country's energy bill if everyone's computer was as energy efficient as new Core U-based computers.
It really wouldn't. Your fridge's power usage eclipses any computer you might have, short of a hardcore overclocked rig running Folding 24/7. To say nothing of electric stoves, A/C and heating, or industrial electricity usage. Hell, at the 20-30 W levels of lighter-powered computers, a couple of light bulbs might make a bigger difference.
All of those things you listed are used only intermittently which dramatically reduces their consumption. Many computers are on 24/7, especially Mac Minis and other things used for media servers.
There was a good article recently about the insane energy demand from DVRs -- they use more energy than any other home appliance, excepting air conditioning used in hot climates.
> they use more energy than any other home appliance, excepting air conditioning used in hot climates.
Hmm... the graph shows 35 W. This standard full-size fridge http://www.danby.com/en/US/our_products/refrigeration/dff100... is rated for 375.6 kWh yearly, that is 42.9 W average. A mostly-idle Mac mini specced around 20-30 W would use well under 10 W on average.
Roughly 260 kWh for 1 year of 30w on all the time (30 x 24 x 365 /1000). That assumes the media server is using 30w all the time. Probably half or a quarter of that (based on no data). Call it 100kWh.
My electric hotplate takes 3kW used for around 10 min a day for moka pot roughly 180kWh (3/6 * 365).
So not tiny but not huge either. I might try to estimate the on/off cycle time of the fridge. I suspect that the kWh figure will be large!
Thanks for running the numbers. The important question is how many personal computers are currently switched on at this exact moment? What's a small improvement to one person can make a huge difference nationally. Just because there are other devices that use yet more energy still (e.g. kettles, fridges, vacuum cleaners, etc.) doesn't mean there shouldn't be a drive for increased efficiency in all our electric devices where possible (in my personal opinion).
Then keep in mind that a "30 W" computer will use much less than that in idle, where it'll be for 90+% of the time. Including auto-sleep, which Macs are good at, you'll be well below 10 W on average.
> doesn't mean there shouldn't be a drive for increased efficiency in all our electric devices where possible (in my personal opinion).
Absolutely, but replacing one energy-efficient sub-30 W CPU with another slightly more efficient CPU won't do huge things to the country's energy bill.
Devil's advocate, but I imagine it'd do huge things to the country's energy bill if everyone's computer was as energy efficient as new Core U-based computers.