15. DVD Playback Battery Rundown Test

Those results may surprise you, which is why I added the processor usage below as well.

When you look at the DVD playback numbers, you always have to keep the processor usage numbers in mind as well, because those numbers explain why there is a difference between DVD playback battery life and Batterymark. In Batterymark, the processor is idle most of the time and thus in the lowest power state the design allows. DVD-playback requires the CPU to do some work all of the time. In the case of Compaq's Presario, AMD's PowerNow! allows the Athlon 4 to run at only 500 MHz, but then 71% processor usage is required to do the DVD-playback. This costs a lot more power than the idling under Batterymark. The opposite is true for Dell's Inspirion 8100. Due to i815's lack of enhanced SpeedStep support, the Pentium III-M is wasting a lot of power running Batterymark. The 16% processor usage for DVD-playback requires just the same power as the idling under Batterymark. However, when you consider the fact that the Inspirion 8100 comes with the same size battery, but even a larger screen than the Presario 725, you can see that Dell's Pentium III-M notebook is still faring a huge amount better than Compaq's Athlon 4 notebook.

Again, ATi's prototype notebook wins the competition with a refreshing 2.5 hours. Dell's Latitude C840 is a bit disappointing, which could be due Pentium 4-M or to GeForce4Go. One of the two has to be blamed for the fact that DVD-playback costs 24.5% of processor usage and thus a lot more power than Batterymark.