Battery Life: Good (60Hz) to Average (120Hz)

Last week we had published our initial battery life report on the S20 series, with some interesting findings. First of all, what needs to be mentioned again is that the new 120Hz display modes on the phones come with a quite large battery life impact. The behavior is exhibited on all our S20 models at hand and I think it’s likely due to the panel itself or the DDIC. Samsung had included various display refresh modes varying from 48, 60, 96 and 120Hz, however we have yet to find evidence of any mechanism that actively switches between the various modes. 

Device-On Black Screen Power Consumption (Airplane Mode)

As such, even on a black static screen, running at 120Hz comes with a quite steep power penalty that’s always present whenever the display is on, costing around 160mW of power.

I had noted that I found our variant of the Snapdragon 865 Galaxy S20 Ultra to have worse idle power than our Exynos phone version. Initially I had attributed this to possibly the SoC or even the nature of the external X55 modem, but since then I’ve also received an LG V60 and that device’s idle power is perfectly normal. The only other thing that differentiates our S20 Ultra here is the fact that it has the extra mmWave antennas and RF systems. It would be interesting to see if non-mmWave variants of the Snapdragon S20 Ultra behave any differently (Tip at our Chinese or Korean readers).

I also had made mention that the “Performance” mode of the Exynos S20 phones seemingly behaved quite overzealously in terms of its scheduling settings, and there was a quite drastic increase in power draw for what was not nearly an as drastic increase in performance. I’ve rerun the battery tests in the “Optimized” settings which doesn’t have the “Increased system speed” option enabled, and I’ve confirmed my suspicion as the battery life figures did improve by some notable amounts. I’ve also tested the Snapdragon in the “Optimized” setting and the runtimes only differed by 2% - for users having the Snapdragon versions it’s thus safe to simply leave that enabled.

Web Browsing Battery Life 2016 (WiFi)

In our web test, the new S20 series end up right about where you’d expect them to. The Snapdragon 865 Galaxy S20 Ultra at 60Hz fares the best amongst the tested models, and now represents Samsung’s longest lasting flagship device. Slightly behind it we find the Exynos S20 Ultra at 60Hz. The difference between the two phones here isn’t very big in this test, and I attribute this to the higher constant idle power draw of the Snapdragon phone which counteracts the much higher compute efficiency of the SoC. The Eyxnos S20+ ends up slightly behind the S10+ phones, but still lasts a good 12.65h in this test.

Once we turn on the 120Hz display modes, the battery life results on all the phones drops quite notably. The Snapdragon S20 Ultra goes from 14h to 11.3h, a 20% drop. The same applies to the Exynos S20 Ultra, with a 20% drop, but for some reason the S20+ sees a larger drop of 25%. In the systems performance section I did mention that there’s some software configuration differences between the Exynos S20 Ultra and S20+, maybe some of that plays part here in the results.

PCMark Work 2.0 - Battery Life

Overall, the conclusion on battery life isn’t quite as black & white as we thought it would be. The key point is to stay away from the seemingly broken Performance mode on the Exynos chipset and you’ll have roughly similar battery life results between the two SoC variants of the S20. Naturally, that’s only being achieved by the fact that the Exynos does showcase worse performance, saving energy by using the more efficient lower performance states more.

What’s valid for all variants of the phones is that the 120Hz display mode is quite the power hog. Samsung probably has the opportunity to improve this by introducing a better managed variable refresh rate mode that actually changes between the different refresh rates based on content, something that seemingly isn’t happening right now. Also switching to lower refresh rates when showcasing static content would be a huge power saver, but I’m not sure if Samsung would be able to actually deploy such a mechanism.

Display Measurement Camera Architecture: Huge New Sensors
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  • Shadowfax_25 - Friday, April 3, 2020 - link

    Excellent article, Andrei. The team over at XDA Developers managed to identify the adb commands which would allow you to set the display to either of the other refresh rates, so I'm sure Samsung could in some way introduce variable refresh rate switching.

    Here's the article for your perusal: https://www.xda-developers.com/samsung-galaxy-s20-...
    Reply
  • Andrei Frumusanu - Friday, April 3, 2020 - link

    Yea I saw that. In an ideal case Samsung would actually implement their own pseudo-VRR mode that switches between the display refresh rates based on content. Reply
  • Shadowfax_25 - Friday, April 3, 2020 - link

    One more thing: it appears as if the commentary around the speaker evaluation is missing. Reply
  • Shadowfax_25 - Friday, April 3, 2020 - link

    Ignore, looks like it was a caching issue on my side. Reply
  • eastcoast_pete - Friday, April 3, 2020 - link

    Yes, but that would make sense, and this is Samsung we're talking about here. Still, there's hope, I guess. Reply
  • yeeeeman - Friday, April 3, 2020 - link

    Andrei, amazing review TBH. You have outdone yourself once again and, fie vorba intre noi, cred ca esti succesorul cel mai potrivit pentru Anand. Esti cel mai profi si cand vine vorba de detalii tehnice, dar si de idei interesante de comparatie intre diferite device-uri. Am scris in romana sa nu se supere colegii tai.
    Please try to add to the energy efficiency table, Ice Lake scores and maybe some energy usages like you have for mobile devices? That would be amazing!
    Reply
  • Unashamed_unoriginal_username_x86 - Friday, April 3, 2020 - link

    avem traducere Google, tipule Reply
  • yeeeeman - Friday, April 3, 2020 - link

    Tipule, era o glumita. Logic ca poti folosi traducerea. Reply
  • abufrejoval - Saturday, April 4, 2020 - link

    Born German with Latin as my first foreign language, and with fluent Spanish and French picked up later, written down Romanian isn't nearly as hard to understand as the spoken language... bine, bine! Reply
  • crimson117 - Friday, April 3, 2020 - link

    $1400 is absurd. There's no way they're worth more than twice as much as a brand new S10. Reply

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