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% 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.
The battery life of the HP EliteBook G5 series laptops fell into the middle of the pack, though the 830 drops into the lower quadrant. In our testing, the EliteBook 830 G5 was able to maintain power for just over five and a half hours under sustained load. The 840, on the other hand, had an extra hour in it. We would have liked to have seen a little more up-time from these devices, but seeing as most people won't be running non stop benchmarks, better life should be somewhat better in real-world use cases.
While testing both the G5 830 and 840 we did notice the processor temperature could spike and throttle at times. Overall, the machines' thermal solutions were mostly able to keep the core temperature below the point where performance would take a hit, but like most slim laptops sporting Kaby Lake-R
processors, there will be times when sustained load might lead to reduced overall performance.
Just like in the previous test the G5 laptops performed more in the middle to lower-end of the pack, and the 840 once again had longer staying power, likely due to a more power-efficient display configuration. It also has a larger, less thermally challenging chassis, resulting in slightly less fan noise and speed as well.