As a next step I set up my machine to run for an hour before entering sleep mode then to hibernate while in Vista – and it did make a decent difference. While asleep, the computer was only drawing between 143 and 167 watts, and wound up using 3.72 kwh for a 24 hour period. This would reduce the annual bill from $175.00 to $131.00, which is an excellent drop in cost. Here is how the settings were configured:
- no screen saver
- turn off monitors after 15 minutes
- set to sleep mode after 60 minutes
- hard drives cycle off after 60 minutes
- Hibernate after 90 minutes.
I have to give it to Microsoft here though, the sleep mode in Vista is vastly superior to that in XP and I had no trouble coming out of sleep mode the half a dozen times or so I awoke my PC. I turned the screen saver off on this test as well to see if it made any changed in the power draw because I have had my doubts as to whether the screen saver turns off after the monitors turn off, or if it continues to run in the background possibly affecting CPU power usage. After checking the wattage used during sleep with both the screen saver turned on and off – it seemed to make no difference at all.
Another thing I discovered throughout this test was that not all USB devices turn off when your machine is turned off. My keyboard still draws power, and will pass power though it to other devices. I have a small Plasma Ball from Think Geek and while it was plugged into my keyboard the power kept flowing regardless of whether the machine was on or off. This surprised me especial since the keyboards LEDs go dark, and it's plugged into the USB ports on the MoBo, not the PCI Card ports.
Still the best solution is to shut the machine down entirely, and let it draw its 35 watts of power while turned off. For those who want to go a step further, you can get a Smart Strip that will shut off all other devices when the CPU shuts down. It is controlled by a single outlet which shuts the entire strip off when the device plugged into that outlet gets turned off, eliminating excess power drain for devices which should be off. This is great for TVs and home entertainment systems as well. Unfortunately it is still just a power strip which I don't use at home. Once this starts getting into battery backups then I will be more likely to get one for my computer.