An Ultrabook’s worth very much depends on its battery life and portability. In this segment, we put the Taichi to the test, to see if its battery performance is good enough to make it through at least half a day. And because it has a secondary high-res display, we’ll also see how much power the secondary screen siphons.
To test the machine’s battery life, we put it through the Powermark benchmark. This benchmark simulates typical usage by opening and closing browsers, videos and other media.
The Taichi’s results for this benchmark was quite disappointing, with most of the blame on the 35Wh battery found in the Taichi. It’s about the same capacity as the batteries found on the Vaio and the Satellite notebooks with similar battery life results.
ASUS, like Toshiba and Sony, likely made the decision to put a smaller battery into the machine, to help lessen its weight and thickness. This makes the machine thinner and lighter, but also cripples it in terms of battery life.
The Taichi stayed alive for 2 hours 53 mins. That’s barely enough juice to get your work done before lunchtime if you started in the morning. If you activate the second screen, the uptime drops to about 2 hours and 31 minutes. It’s still a bad result, but it was also a pleasant surprise. We expected the second display to use up much more battery than just dent the uptime by a mere 27 minutes.
Unfortunately, since the Taichi’s normal battery life is pretty weak, 27 minutes translates into a significant chunk of the machine’s battery life. That means users might need to plan way ahead if they want to utilize the secondary screen when the machine is unplugged.
Our portability index is a formula that tries to quantify how portable a machine really is. It basically uses elements like a machine’s battery life, mass and volume to tell us if a machine is worth your time to carry it about.
The best direct comparison would be with the Sony Vaio Duo 11, which has the same dimensions and weight. Here, the Vaio Duo 11 is considered to be more portable due to its better battery life. The Taichi’s single display battery life also couldn’t help it keep up with the Vaio Duo 11.
However as an Ultrabook, the ASUS Taichi 21 is on par with most of the recent Windows 8 convertible Ultrabooks out in the market right now. We find that the Taichi’s 11-inch display size a major factor that helps it keep up with the portability of the 13-inch Ultrabooks. Perhaps ASUS shouldn't have used such a high speed processor that's not so beneficial for this class of products.