Greener Than Expected
I just picked up one of the new Mac Minis that Apple released this summer, which added the Thunderbolt port, dropped the optical drive, and ship with the new Intel i5 and i7 CPUs. Given that this is largely nerd talk, most of that isn’t particularly germane to the story, except the new processors, which were originally designed for laptop use (they’re also shipping in the new Thunderbolt-equipped MacBook Airs).
This computer replaced a five year-old Mac Pro; the very first tower Mac that Apple shipped with Intel CPUs.
In a nut, the Mac Pro had been a trusty computer, and actually still works splendidly. The only trouble is that it takes up a bunch of floor space, guzzles electricity, and – most painfully, during a NYC summer – kicks off a ton of heat. I was looking to lower all three profiles.
As part of my intention to use less electricity, I also picked up a Digital POWERCENTER 650G “GreenPower” surge protector, by Monster. It looks like this:

For anyone unfamiliar with Monster’s “GreenPower” products, they describe the line as follows:
Monster GreenPower™ is a revolutionary new way to automatically reduce energy waste and save you money. Simply plug your computer into the GreenPower Control socket. When it’s turned off or goes to sleep, the other GreenPower sockets switch off, automatically eliminating energy wasted by peripherals, like your monitor and scanner, when you’re not using them. When your computer turns back on, the GreenPower sockets automatically power up again.
The gist is that the surge protector has one “master” socket (labeled above as “computer”), into which you’re meant to plug the “primary device”, and a number of “subordinate” sockets (for the various accessories attached to the computer), which only get juice when the device on the “master” socket is consuming 17 Watts or more of power1. The surge protector also has a single “independent” socket (labeled “modem” in the photo above), into which you can plug a device that isn’t part of the “master / subordinate” equation.
So, following the direction suggested by the labeling, I plugged the Mac Mini into the “master” socket, and plugged the monitor, printer, speakers, and USB hub into the “subordinate” sockets. The “independent” socket remained unused.
Then I turned the computer on. The “subordinate” devices remained off for a few seconds. But once the startup process was in full swing, the monitor came to life, I heard the printer begin to do its “wakeup dance”, and the speakers popped as power flowed to them!
Then the login screen came up, and the monitor, et al lost power.
I figured that I just needed to get past the login and start using the computer, and that this would keep everything juiced up. So I typed my password and hit the ENTER key. Immediately the monitor came back to life, the printer did it’s initialization dance, and the speakers popped to life again, while the Finder launched, my “startup items” got spawned, and Lion restored my application state from before I had shut the computer down in order to replace the old surge protector.
As I reached to the trackpad, however, the monitor and the rest of the devices plugged into the “subordinate” sockets all shut off again; the Mini simply did not consistently draw enough power to meet the 17 Watt minimum required from the “master” socket in order to activate its subordinates.
Remember when I mentioned that i5 Intel CPU back at the top? Apparently they are particularly energy efficient.
No wonder Apple put ‘em in the Air.
I started to wonder, however, if I’d just bought some new but utterly useless thing, destined to merely collect dust.
So I plugged the monitor into the still-free “independent” socket, and managed to safely shut the computer down again. While was clear to me that the Mini couldn’t be the device plugged into the “master” socket, it simply wasn’t safe to plug it into the “subordinate” sockets. So it had to take the “independent” socket, while some other device was to be used to drive the “master” socket.
At first, I tried plugging the monitor into the “master”. It seemed like a reasonable selection, given that putting the computer to sleep would cut the video signal, hence putting the monitor into standby mode.
Switching it on, I learn the monitor had no trouble driving the master socket. At all.
But now I had two devices (the Mini and the Monitor) which would be sipping power 24 hours a day, even in standby mode. My savings were diminishing. I also keep a clamp light next to my desk, which I always turn on when I’m using the computer. I’ve presently got a 60W bulb in it; which uses far more than the 17W minimum required to drive the “subordinate” accessories. And it draws ZERO Watts when switched off.
And so I’d found the winner.
So, in the end, the device powering setup on the surge protector looks like this:
| Master | Lamp (60W on; 0W off) |
|---|---|
| Subordinates | Monitor, Printer, Speakers, USB hub (various power consumption rates) |
| Independent | Mini (apparently mostly south of 17W on; ~4W in sleep) |
There is also no longer a Mac Pro on the floor, claiming 6″ of space between the wall and my desk; and the corner remains much cooler, letting me run the AC at lower levels.
Footnotes
- I couldn’t find this official information on Monster’s website, but here’s a Google search which should offer up some reference material for the curious ↩





