Battery Life
Inside the Surface 3 is a 28 Wh battery, which is fairly average for a tablet of this size. The Surface Pro 3 comes with a significantly larger 42 Wh battery, which is needed for the more power hungry Intel Haswell CPU and the slightly larger display. Despite the Pro 3 coming with a larger battery than the Surface 3, Microsoft claims the Surface 3 will last an hour longer during video playback (10 hours versus 9 hours).
During my time using the Surface 3 over the course of a few weeks, I found the tablet's battery life to be acceptable. While I don't think the Surface 3 is the sort of device you'll sit down and use for an entire day, I did achieve around seven hours of typical usage between charges. This isn't spectacular for a 10-inch class tablet, where I would like to see at least 10 hours of usage from a full charge, but at the same time I didn't think that seven hours of life was inadequate by any means.
From our battery life benchmarks, the Surface 3's battery life was disappointing. For starters, the tablet fell three hours short of Microsoft's video playback battery life figure, which indicates the company tested with a lower display brightness than I did. It also performed worse than the other tablets I had tested with, including the similarly-sized Lenovo ThinkPad Helix that features a more powerful Intel Core M processor. Running one of our older video playback benchmarks showed that the Surface 2 outlasted the Surface 3 as well, which isn't too surprising considering the Surface 3's performance increase.
In our intensive Wi-Fi browsing benchmark, I was again disappointed with the Surface 3's results. In this benchmark the Surface 3 lasted just as long as the ThinkPad Helix, but fell well short of the Miix 2 8, which is an 8-inch Bay Trail tablet. Getting around eight hours of battery life in this benchmark would have been a good result from the Cherry Trail Atom-based Surface 3, considering its size and performance profile, but it disappointingly fell a few hours short.
For intensive gaming the Surface 3 performed decently, but it's unlikely you'll be able to do more than a few hours of consecutive gaming on this tablet without plugging the device into its included 13W micro-USB charger.