Battery Life

The Xperia X Performance includes a non-removable 2,700 mAh (10.4 Wh at 3.85V) battery, which is smaller than previous Sony flagships. I'm not sure why Sony hasn't included a larger battery in this 8.7mm thick handset - two other 5.0-inch phones, Sony's own Xperia Z5 (2,900 mAh) and the Huawei P9 (3,000 mAh) - pack larger batteries in slightly thinner bodies.

I suspect Sony was hoping the Snapdragon 820's energy efficiency improvements would offset the smaller battery capacity of the Xperia X Performance. Unfortunately, this isn't the case, which leaves the X Performance with poor battery life compared to its peers.