In the following benchmarks we employ two very different battery life tests, Battery Eater Pro and a custom 1080p HD video loop test developed in-house, to prove out battery life with our test group of machines. In all tests, Windows 10
Quiet Hours has been enabled and the displays are calibrated with lux meters
on pure white screens to as close to 115 lux as possible. For the average laptop this is somewhere between a 40-60 percent brightness setting.
Since laptop displays significantly affect power consumption and battery life, it's important to ensure a level playing field with respect to brightness of the display for battery testing. However, since many laptop displays vary in brightness at each respective setting in Windows, this calibration with the meter is critical to ensure all displays are set to as near identical brightness as possible before testing.
Battery Life - How We Test:
Our custom HotHardware video loop test takes a 1080p HD video with a 16Kbps bit rate and loops it repeatedly, with 1-minute break intervals in between. A timer log file increments minutes of up-time every minute— along with the grand total—before system shutdown is stored in the log. This is a lighter-duty test that is still a bit more strenuous than many office productivity tasks, but it's not nearly as taxing as the load Battery Eater puts on a system.
Driving a bright, 4K resolution display simply eats battery life, and in this case, the XPS 13 chugged along for a little over five and a half hours before running out of juice. That ranks it in the lower-third among the systems we compare it against. Interestingly, the late 2017 model XPS 13
leads the way, but that system was sporting its 1080p version display and a larger 60 Whr battery back then.
Compared to last year's model, there is still a sizeable gap in battery performance when you compare 4K display models from 2018. However, we should qualify these current early results may be temporary. Dell
is in the process of updating the firmware on the new XPS 13 (9380), and we are told it will be better optimized for Intel's Whiskey Lake
processor power profiles and thermal management. This should improve battery life, perhaps even dramatically. We should also underscore that moving to the 1080p version display for this machine should improve battery life significantly as well, at the obvious trade-off of less screen real estate. For now, however, we can only test what is available, and what we have is represented here. When and if an update arrives that could affect battery life, we will re-test if possible.
Battery Eater Pro is more demanding on battery life, and so the scores here are always lower for all systems. The XPS 13 lasted for a little over two hours in this test. That ranks it in the same general area, and again, this could see an improvement with updated firmware.
Dell XPS 13 Acoustics And Thermals
Cooling is always a concern when it comes to thin and light systems, particularly ones that cram high-end hardware inside. However, this has historically been a strong suit of the XPS 13. If you were to pry this thing open (not advisable), you would find heatpipes, fans, and Gore Thermal Insulation material that Dell says has a lower thermal conductivity than air. This is applied to selected areas of the heatpipes that cool the CPU.
The XPS 13
never felt uncomfortably hot during test. It warmed up, as we would expect, but never actually got toasty—certainly not to the point where we could fry a steak or anything crazy like that. Just as importantly, the system stayed quiet. The fans don't kick on all that often, and when they do, it's more of a polite whisper than anything else. This is an exceptionally quite machine the vast majority of the time.
One question that inevitably comes up is if we can hear any coil whine. This has not been an issue for us. We do hear a faint electrical sound if we jam our ear up against the laptop, but it otherwise is not audible.