tow.com

During the three weeks we were in China, the computers in our home office were turned off. Our electricity bill for the month was $24 cheaper than the previous one. In fact, our electricity usage has been steadily going down after we switched to compact fluorescent lights (CFL) and became smarter about turning off unused appliances.

I suspect much of the power savings came from the fact that my PowerMac Quad G5 was getting a well-needed rest. I’ve been using this machine, along with an Apple 30-inch Cinema Display, for over two years. The MacBook Pro isn’t as fast as the Quad G5, so it’s not about to replace the PowerMac when I have photos to process or our film to edit. For mundane tasks like email and web browsing, however, it’s perfect and much more portable. In addition, the MBP has distinct advantage over the Quad G5 in the energy usage department.

I used a Kill-A-Watt power meter to measure the power usage of the Quad (with the 30-inch display) and MacBook Pro performing various tasks.

Note that my PowerMac Quad G5 has 6GB of RAM, two 750GB internal SATA drives, an Nvidia 7800GTX video card with 512MB of RAM, and a TeraCard PCI-E SATA card. An iSight camera is also connected to the PowerMac via FireWire. The MacBook Pro has 4GB of RAM and a stock 160GB hard drive.

The Quad G5 is certainly powerful and power hungry! It certainly doesn’t help that I have even more peripherals attached to the Quad than I was measuring in my tests. In addition to the 30-inch Cinema Display, I have a FireWire iSight camera, a 17-inch Studio Display as a secondary monitor, and a WiebeTech RTX-400 4-bay external SATA box (it’s usually off unless I’m processing photos or editing video). Fortunately, everything is hooked up to a solid APC UPS, so I’m good (for a few minutes) in the event of a power outage.

Even if I plugged the 30-inch display into the MacBook Pro, the laptop would still be more energy efficient than the Quad alone. I read that the new Mac Pros are pretty good compared to the Quad G5, which appears to be the most energy inefficient Macintoshes ever produced.

We’ll never get to the electricity usage levels of Felix in Colorado. Our goal is to get our utilities costs under $100. Having a pool makes it difficult, as it uses tons of water and electricity. With a switch in the way we use our computers, however, I think we can achieve the goal!