How Power-Efficient Are They?

Now, let's take a look at the power-efficiency of these new processors. This is especially important because the PXA3xx processors are designed to power mobile devices. Their power-efficiency will be a major factor in determining the battery life of those devices.

Let's start with a test Marvell did by recording a QVGA video clip (24 fps, 384 kbps) in the WMV format on both the PXA320 and the PXA270. Here, both processors have been normalized to a 624MHz core speed.

The PXA270 recorded a power usage of 530mW while the PXA320 only used about 327mW to record the same clip. In other words, the PXA320 uses 38% less power than the PXA270 for the same task.

Now, that was for a video recording. What about audio and video playback? After all, we tend to play audio and video files more often than recording them. Let's take a look.

In this test, Marvell compared PXA310 prototypes against the NEC 902i and Motorola E680i. The Motorola uses the older PXA27x processor while the NEC 902i uses the OMAP2420 processor. All three phones use the same operating system.

When the results are normalized against the 900mA battery, the PXA310 prototype demonstrated a remarkable increase in battery life. Marvell claims it can continuously play audio files for about 14.6 hours and MPEG-4 videos for just over 7 hours.

Very impressive results, since the PXA310 prototype has about 1.3x to 2.11x longer battery life than its competitors. However, there's no way to tell if the increased battery life is entirely due to the processor.

For those who worried about H.264 playback capabilities, well, these processors support H.264 decoding.

The low-end PXA300 is capable of 30fps at the QVGA resolution of 320x240. The two higher-end processors are capable of 30fps at full VGA resolution.

But what about battery life? Marvell takes a look at that by comparing the Zylonite DVK which uses the PXA310 against a few competitors.

Here, you can see various devices being compared on audio and video playback. But the most important thing to look out for is the H.264 playback results.

Even ignoring the results of competing devices, it's impressive to see that the Zylonite DVK can play 3Mbps H.264 video at 30 fps and at full VGA resolution for almost 4 hours! Running a lower bitrate file at 15 fps increases that to just over 6 hours.