Battery Life and Conclusions
My battery testing with the Xiaomi Mi Pad 7.9 is a bit limited for now as I was only able to run our now standard PCPer Wi-Fi test. In this test, display brightness is normalized and we run a script which cycles through websites every 30 seconds.
With a result of just over 9 hours, the Tegra K1 tablet was able to pass up that of the Tegra Note 7, and nearly matched the ASUS MeMO Pad 7 using the Intel Z3745 Atom processor. The ASUS Nexus 7 (2013 edition) runs for a more impressive 11.5 hours, easily overtaking the other Android tablets we tested.
This graph is a bit more interesting, as it presents a calculated estimate of power consumption of each tablet, including the SoC, memory, display, etc. These numbers were calculated by finding the total battery size of each tablet (in Watt-hours) and then dividing that by the actual number of hours the tablet ran in our testing. Obviously this result isn't going to be 100% accurate, and takes into the calculation the other components in the tablet, not just the SoC. Still, it's an interesting look at the overall efficiency of the Tegra K1 platform.
In this graph, a lower number is better, as it indicates how power is being consumed. The lower this number, the longer the battery in the device would last. Even though the Tegra K1 is able to hit 9 hours in our Wi-Fi browsing test, it clearly requires a much larger battery to do so. The K1 comes with a 24.7 Whr battery; the Nexus 7 only needs a 16 Whr battery and lasts more that two hours longer.
I have a lot more battery testing that I would like to do with this device and a couple of others shipping very soon. Hopefully we'll be able to investigate gaming-time as well, something that I think needs to be considered more heavily as NVIDIA starts to target the gaming angle (even more exclusively) for its upcoming products.
The Xiaomi Mi Pad 7.9 is an interesting product that will have little impact on the US market. As a device that is not intended to be imported here, it is really just an educational venture for us to test it and evaluate it. Even so, the results were damned impressive and the performance of the Tegra K1 SoC really came through in both the CPU and GPU results. By integrating a full Kepler SMX in the design, the graphics performance of the Mi Pad is unrivaled in the tablet market. However as it stands now, there are a very limited number of applications or games that can even truly show the performance the K1 can offer. As the K1 implementations increase though, that will likely improve.
I paid $344 for this unit before shipping costs, off of AliExpress.com. Do I recommend that our readers go out and make the purchase as well? Likely not, but for those that are curious and demand the latest technology today, it's not a horrible investment. I think I can get away with telling you that other tablets using this SoC will be available pretty soon domestically, so you should probably wait for something you can pick up on Amazon or Newegg.
My time with the Xiaomi Mi Pad 7.9 has been fun. I only hope that NVIDIA and its partners can find a better way to highlight its benefits with games and software.