iMac keeps its power promise, PC challenge issued

Before I ever tested the Intel-based iMac, I already had the number I needed to be throughly impressed: 120 watts. That's Apple's rated maximum power consumption.

I have a duty to report that this figure is inaccurate. Results of the measurements I took on a 20-inch iMac were better than Apple's specs.

At typical interactive use--both hands in constant motion, flipping among 6 or so open apps--iMac draws 80-85 watts. With both of Core Duo's cores cranked to 100 percent utilization, I got a steady 95 watts. Lightly or heavily loaded, you can use iMac as a reading light and still save on your electric bill.

Let's jot 95 watts in the margin. My wife's standalone 19-inch LCD measures in at 32 watts, including the green power LED. To approximate the power the 20-inch iMac's would consume if it were a generic headless PC, take iMac's loaded 95 watt draw and subtract 32 watts for the display. That leaves you with...

...a 63 watt personal computer. That's with two 2 GHz cores kicking at 100 percent, 802.11g and Bluetooth active, 1 GB of RAM and 128 MB of GDDR3 graphics RAM all churning away.

PC types, here's a homework assignment for you: Please point me toward a desktop PC, sans monitor, that hits these specs. No embedded, industrial, notebook or homebrew machines. Don't forget those two cores, now. If it can't run OS X, I'll let that slide.

I'm not assuming it can't be done. My mind and comments box are open.