Dell DTR Laptop Shootout - M1710 vs. E1705by Jarred Walton on May 30, 2006 1:30 PM EST
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Power ConsumptionFor power testing, we removed the battery from the laptop and measured system power draw at the wall outlet using a Kill-A-Watt device. All three laptops were configured to run at maximum performance when plugged into AC power. We tested under stress conditions as with the noise and temperature benchmarks, but we also added a couple more results. First, we have peak power draw, which is often quite a bit higher than the typical average maximum power. We then got a rough estimate of the average power draw under full load, as well as a maximum power draw when only the CPU is placed under full load using two instances of Folding@Home. Finally, we have idle power draw, where the system has been sitting with no applications running for 10 minutes or more. The screensaver is disabled, as is the hard drive sleep mode.
Why would anyone want to get the X1400 in such a laptop? Obviously, because it uses far less power than even the GeForce Go 7800. While 10 to 12 W might not seem like a big deal, that represents 25 to 30% more power draw. Considering that the battery is rated as 80 WHr, a load of 20 Watts will last roughly 4 hours while 30 Watts will only last 2 1/2 hours. That's the theory anyway, so we'll turn to our battery tests to find out exactly how long the systems can run under typical usage.
We also tested power draw with the LCD at maximum brightness and minimum brightness. The total difference was only 6 W, indicating that the LCD manages to be very power efficient. There are eight brightness levels on the LCD, and power draw scales pretty much linearly as you go from level 1 to level 8. The default brightness when running on battery power is 3, although if you use the system in direct sunlight you will definitely need to crank that up. Going with the maximum setting will reduce your battery life somewhat, but you shouldn't lose more than 30 minutes of battery life at worst by setting it at maximum intensity.