Lenovo Yoga 920 Review : Battery Life And Acoustics
At HotHardware we employ two very different battery life tests, Battery Eater Pro and our own custom 1080p HD video loop test, developed to prove out battery life. For both 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 will equate to a Windows brightness setting somewhere between 40 - 60%. Laptop displays vary significantly in terms of output levels and their effect on power consumption and battery life. It is important to ensure a level playing field during battery testing and adjusting the brightness to a specific output ensures accurate results across multiple platforms.
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 Lenovo Yoga 920 we had in for testing finished fourth among the systems we tested, trailing Lenovo's 2017 ThinkPad X1 Carbon and more recent HP and Dell offerings. Additionally, our Yoga 920's display is FHD but we would assume that the 4K variant would offer less playback time.
The other test we utilize for battery testing is Battery Eater Pro. It wears systems down more quickly by placing a heavy load on all subsystems, including processor, graphics, memory and even some minor file transfers to storage. This is truly a worst-case test that will give you a sense of how a machine will hold up under heavy strain, like when gaming or under taxing, continuous content creation workloads, for example.
The Yoga 920 did well in the Battery Eater Pro test. While it did not outshine the rest of its competition like it has done in a lot of the other tests, it fell right into the middle of where we would expect it. Most current generation Intel 8th Gen machines can process more workload in the same previous 15 Watt TDP envelope as last year and the Yoga 920 didn't disappoint here, though it really didn't stand out either.
Acoustics & Thermals
Lenovo's Yoga 910 previous generation machine wasn't nearly as tame as the new 920, noise-wise. Lenovo engineers appear to have taken customer feedback to heart and we are glad to say that is not an issue with the Yoga 920. Under normal working conditions, office apps or browsing the web, the system's fans rarely spin up and if they do, it is not to very audible levels. When the system is running more strenuous tasks, like encoding video or running a stressful benchmark, its fans will spin up and stay running, but for most it will sound like a gentle breeze rather than a whine. This system is by no means loud and for those looking for performance with reasonable acoustics, the Lenovo Yoga 920 is a big step-up from its predecessor.
Thermals with the new Yoga 920 aren't a concern either. To produce these heat maps, we looped 3DMark and checked each zone with an infrared thermometer. The warmest part of the machine was the three inches closest to the watchband hinge. The area directly beneath the number seven key is the the warmest., though its completely reasonable and comfortable. This is where the system houses the processor. In all of the other areas the system does not heat up to notable levels. The section above the touchpad, and the three inches closest to the user, was the coolest. Lenovo made great strides in performance, power consumption and most definitely in terms of the thermal and acoustic characteristics of this new machine.