Source: Dell
Best answer: Opting for a 4K display on any notebook will draw more power and thus reduce battery life. However, you should still enjoy around six hours of use, taking into account the 86Whr battery upgrade on select Dell XPS 15 9500 configurations.
Latest and greatest: XPS 15 9500 ($1,300 at Dell)
Better display draws more power
Dell considered the increased power draw of the Dell XPS 15 with a 4K display, which will consume considerably more than the 1080p option, especially with the increased resolution and touchscreen support. The base models come with a 56Whr battery pack, while more pricey configurations come rocking an 86Whr power plant and are better suited for the 4K upgrade.
That's a little short of double the amount of capacity for storing power for use on the go. Strangely, this won't provide more uptime with each charge per se but will ensure the upgraded internals won't hurt the acclaimed battery life. It does also mean the laptop hits 2kg with the better panel and better battery, up from 1.8kg. Something else worth considering if portability is essential to you.
Another factor to consider is the Intel Core i7 or Core i9 processor and optional dedicated GTX 1650 Ti GPU, both which will also have cause further strain on the battery, especially when you're watching videos, doing some work, or gaming. Enjoying media should result in several hours of entertainment, while gaming and other intense workloads will see the battery deplete at a considerable rate.
Getting better battery life
If you want a 4K display and will make the most of it, it's recommended you make the upgrade. If battery life is more of a concern, we recommend picking up a Dell XPS 15 with a 97Whr battery, the 1080p display, and Core i5 processor to get the most out of the notebook on a single charge.
If you find yourself not getting much uptime with each charge on your XPS 15, be sure to try these tricks out. There's also the possibility of adding an external charger into the mix, to give you some more power on the go. Dell's own Power Companion is a great choice.
Our pick

Dell XPS 15 (9500)
The 4K version of the Dell XPS 15 lets you get more done.
If you're conscious about battery life and getting the most out of your laptop, it doesn't matter too much whether you choose the 1080p or 4K display on the XPS 15. The larger capacity battery with the 4K display models will keep you computing for just as long.
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