My initial tests of AMD's Ryzen 5 2500U APU gave us a fine picture of the APU's performance, but we admittedly didn't test battery life in that initial article. Part of the reason for that omission was to avoid drawing unfair comparisons between the 15.6" HP Envy x360 that plays host to the Ryzen 5 2500U and the 14" Acer Swift 3 machines we used to represent Intel's Core i5-8250U.
Although the jump in screen size might not sound large on paper, the practical effects of the Ryzen system's bigger screen on battery life are likely quite significant. Getting the same light output from a bigger panel requires more power, as just one variable, and the HP system also has a pen digitizer in its LCD panel with unclear power-management characteristics.
So long as we keep those caveats in mind, though, we can at least offer a basic picture of how long the Ryzen 5 2500U lets the Envy x360 run on battery using a couple different tests. The one quirk of our test rig compared to the $750 default configuration you'd get off the shelf at Best Buy is the Samsung 960 EVO 500GB SSD we're using as our system drive. A hard-drive-only Envy might run for less time, though Windows' power-management features should generally take the mechanical hard drive out of the equation when it's not in active use.
To run these tests, I set the Envy's screen brightness to 50% and left Windows on its default Balanced power plan. The only changes we made to that default configuration involved disabling the operating system's Battery Saver safeguard and forcing the screen to remain on over the entire course of the test.
First off, I ran the Envy's battery down with TR's Browserbench. This benchmark runs a loop of an older version of our home page with plenty of Flash content sprinkled in, along with some cache-busting code to make for more work on the test system. Browserbench is getting up there in years, but it is repeatable and still offers a decent proxy for light web use. We're working on a new version of Browserbench that runs through a range of real-world web sites, but for now, the old version will have to do.
When the Envy shut off automatically with 5% remaining in its juice pack, it registered six hours and 12 minutes of battery life under Browserbench. That's well short of HP's claimed 11-hour battery life figure, but it would at least get you from New York to Los Angeles on in-flight Wi-Fi. To try and see just how good that figure was among similar machines, at least, I scoured the web for reviews of comparable PCs.
Reviews of Envy x360s with Intel eighth-gen processors inside remain scarce, but I did find that an Intel Kaby Lake-powered Envy x360 with a configuration and battery similar to that of our Ryzen system turned in six hours of web-browsing battery life for the folks at Laptop Mag. That test suggests Ryzen Mobile could be delivering competitive battery life against similar Intel systems, but it's hard to say just how competitive the Ryzen 5 2500U is without more in-depth (and possibly less representative) directed testing on our part.
Web browsing isn't the only use of a machine on the go, of course. To test video playback, I set up Windows 10's Movies and TV app to loop the 1920×1080, 55 Mbps H.264 version of the Jellyfish reference video until the Envy's battery died. I confirmed that Movies and TV was firing up the GPU's video decode engine using the GPU-monitoring tools in the latest version of Windows 10's Task Manager before letting the test run. Incidentally, here's a full accounting of the Ryzen APU's video-decoding capabilities, as ferreted out by DXVA Checker:
After displaying four hours and 37 minutes of pulsating sea life, the Envy x360 went dark once more. That result parallels the four-hour-and-32-minute run time achieved by the folks at HotHardware in their video playback testing, although the site claimed it had to run its x360's screen at 100% brightness to achieve a comparable output level with its other laptops. While I didn't run our Envy x360 so brightly, HotHardware's results still suggest we can be confident that our run time is in the right ballpark.
With these two tests in the bag, it seems like our 15.6" Ryzen system delivers only average battery life for its size class. I'd still caution against drawing too many comparisons between the Envy x360's battery life and that of other laptops at this stage, though. Implementation differences matter, and we don't know how Ryzen Mobile will behave in smaller and lighter systems. It's still early days for drivers and firmware, too. Our preliminary results and research suggest that Ryzen Mobile's battery life could be competitive with that of similar Intel systems', though, and that's as good a bit of news for AMD as its chip's well-rounded performance.