I have an i5 27" iMac and have had for a couple of years, but have been getting a bit paranoid about energy consumption in the house and had a look at the power usage when it sleeps, and when it's active.
I've found that when active, it's using about 120w, if I have energy saving configured to put the computer & display to sleep after x minutes, it then consumes 80w. HOWEVER, if I put it to sleep using the Sleep on the menu, it is a much more efficient sleep and uses only 11w.
So my question is, is it supposed to sleep "properly" when configured to sleep in the energy settings, or is this almost-perfect sleep only meant to be attainable by the Sleep menu (and by scheduled sleep also, that seems to work properly).
I've spent a few hours trying everything to get it to fully sleep on the inactivity timer but all to no avail. I've unplugged all USB devices, just leaving keyboard & BT magic mouse, I've tried starting in safe mode with the left shift key held down, no joy there. I've cleared the "wake for network access" checkbox. Also had a play with pmset, but couldn't get it to do anything better and I'm starting to feel like I'm chasing something impossible here.
I installed narcolepsy, but it insisted on shutting me down every 5 minutes regardless of whether it was in use. I also tried PowerSleep, but it would go to sleep even if iTunes was playing, so no dice there as I permanently have iTunes loaded and don't want it sleeping when I'm playing out to my Airport Express units.
I've read a lot of posts on this, but no one seems to say whether or not the full-sleep should be achievable through the Energy Saver timers and I'm starting to think it's not possible...