To facilitate use in the shared tabletop mode, Sony has built in a 5000 mAh battery, which can run the system for up to 3 hours sans power cord, depending on the brightness setting and use mode.

Since the Tap 20 carries an ultra-low-voltage mobile CPU, the performance is somewhat lacking compared with that of other all-in-one PCs. PCWorld is in the process of building the new WorldBench 8 suite for Windows 8 testing, but it isn't quite ready yet. We were able to run PCMark 7, including storage tests, plus startup times. In comparison with previously tested AIO systems running Windows 7, the Tap 20 is seriously deficient in sheer CPU performance: Although you can use the system for video editing or gaming, those activities are most certainly not its strong suit.

For example, on the office productivity test, the Tap 20 garnered a score of just 730, less than half the mark of Lenovo's ThinkCentre M92z. And the Sony's image-editing test took 596 seconds, versus 157 seconds for the Lenovo, in average usage scenarios. Some of the performance issues are attributable to the slow, 5400-rpm laptop-style hard drive.

On the other hand, the power usage is low. The idle power of the Sony Tap 20 is just 23 watts, about half the 41W idle power of the Lenovo all-in-one.