The Samsung Galaxy S21 Ultra & S21 Review: The Near Perfect and The Different

Battery Life - Actually Great

Battery life of the S21 series is interesting as there’s two opposing factors that come into play. We’ve seen that this generation of SoCs are actually less energy efficient than last year’s iterations during interactive workloads. This comes at the benefit of higher performance, but generally it’s accurate that the new chips use more power. On the other hand, we also have more efficient displays, and high-refresh-rate operating modes.

On the Galaxy S21 Ultra, both software and hardware adaptive frequency work on a frame basis, allowing it the maximum power efficiency benefits even during 120Hz operation. Together with the much more luminance efficient screen, we should be looking at outstanding battery efficiency.

The regular S21 is more interesting as we hadn’t had the opportunity to see Samsung’s adaptive refresh mode on a display which doesn’t support hardware LFD. Here, the mode switching between 120Hz and 60Hz is on a coarser software level – the display will switch to 60Hz on static screens, but only after around a second of inactivity. That’s actually still great for power efficiency compared to the constant 120Hz of the S20 series, which means that in general every-day scroll-and-read behaviour, the 120Hz mode of the S21 and S21+ should still be much more efficient than their predecessors.

In our web-browsing test, the results here are slightly different to our provisional test results we had published a few weeks ago- notably on the 120Hz runs.

Nevertheless, the results for the S21 Ultra are outstanding. Even though in theory the SoC is more power hungry, the new display is so much more efficient, that we’re seeing the S21 Ultra takes a large lead of 13% at 60Hz for the Snapdragon variant. The generational differences for the Exynos variants here is much smaller due to how more much responsive and aggressive the new SoC is, which mostly counteracts the new luminosity efficiency of the screen.

In 120Hz mode, the new Ultra devices both take massive leaps over their predecessors- showcasing the new adaptive frequency and LFD mechanisms and how they make 120Hz viable in every-day usage.

Even the smaller S21, the software based adaptive refresh helps a lot as the shift from 60Hz to 120Hz now only costs around 8% in battery life, whereas last year on the S20+ it had a +25% impact.

People will notice the Snapdragon S21 Ultra has a larger delta between its 60 and 120Hz modes, and I think that’s because for some reason the Snapdragon 888 behaves much less aggressive in its 60Hz setting, while the Exynos S21 is tuned to be equally responsive regardless of refresh rate, which is a software discrepancy between the two phones.

Overall Battery Life: Great

In general, the S21 Ultra’s battery life is just fantastic thanks to the new generation display and its heightened power efficiency. The advantages here will vary depending on how you use it – if you tend to use it in dim environments at lower brightness, you might not see the improvements as much as if you’re in a bright scenario and tend to use your phone at high brightness levels. The brighter it will be, the better the S21 Ultra will fare. In super bright scenarios, the phone will be unmatched.

For the S21, and likely applicable to the S21+ as well, battery life is also great. While not as powerful as the Ultra’s adaptive refresh mechanisms, the new software-based implementation on the S21 means that 120Hz is also a very viable option this generation.

While we’re seeing battery life this generation still favour the Snapdragon chips, the Exynos this year isn’t all that far behind, and given the general user experience equality between the two phones, it’s not a major point of contention anymore.