The Asus Zenfone 3 ZE552KL sports a 5.5" screen with 1080p resolution. It's a Super IPS+ panel with excellent viewing angles and impressive brightness - Asus promises 600nits! It also promised 100% NTSC color coverage, which would make this a truly impressive display.
Our measurements confirm the 600nits of brightness claim - easily achievable in manual mode, Auto mode offers no additional boost so you are in full control. At full blast, the black levels remain quite reasonable at 0.45nits for 1,300:1 contrast ratio. That's comparable to the iPhone 7 Plus screen and better than the LG V20 screen.
The Zenfone 3 screen has amazing range, it managed to get down to just 4.9nits when we dragged the brightness slider to minimum. There's also a blue light filter toggle in the notification area to further improve late night viewing (checking a 600nit phone at night is painful, trust us. Also blue light can mess up your sleep cycle).
|Display test||100% brightness|
|Black, cd/m2||White, cd/m2|
While bright and with high contrast, the high reflectivity of screen keeps its sunlight legibility score relatively low. LCDs of similar brightness do better - sometimes much better. True, they are usually flagships, but a 3+ score is not unexpected when we're talking 600nits. Even dimmer screens can score higher (both LCD and AMOLED).
From the settings you can access the Splendid app, which is used to adjust the screen colors. The default Balance mode is not that accurate with a cold white balance and an average deltaE of 5.5 (max 9.7). Vivid mode pumps up the contrast and saturation for extra punch at the cost of accuracy.
We found that staying on Balance mode and dragging the Color temperature slider all the way to the right offered much better color accuracy - average of 2.8 (very good) and improved maximum of 5.7. Not as good as the leading flagships, but better than the LG V20 and close to the Pixel XL.
You can manually adjust the Hue and Saturation sliders, which can create some psychedelic results, but is not particularly useful otherwise.
The VisualMaster 3.0 technology promises 100% NTSC color coverage. For comparison, sRGB is just 72% NTSC. This is distinct from color accuracy, it's about how many colors can be displayed (similar to Apple's Wide Color). Of course, you'll need the right content to benefit from this and most content out there is limited to sRGB.
The Asus Zenfone 3 ZE552KL is based on the Snapdragon 625 chipset, which delivers Cat. 7 speeds - up to 300Mbps downlink and 50Mbps uplink, thanks to 2-carrier aggregation. Both SIMs can be used for LTE.
The phone has two phone lines, which enjoy VoLTE for higher quality sound. Asus says the Zenfones are more resilient to signal dropouts than, ahem, a certain Cupertino-based competitor. The noise reduction will help VoLTE do its best even in noisy environments.
Local wireless connectivity is shored up with dual-band Wi-Fi up to 802.11ac. Bluetooth is version 4.2, then there's NFC. Positioning is covered by GPS, GLONASS and Beidou.
The Zenfone 3 has a USB Type-C port on the bottom, which is wired only for USB 2.0 speeds.
Update: We completed the battery tests, here are the full results.
The 3,000mAh battery capacity is about average for a 5.5" phone, certainly, there are others with a few hundred milliamp hours more. The phone bets on the super-efficient Snapdragon 625 chipset, which is built on a 14nm fabrication process (most mid-range chipsets are built on a 28nm process, which is not nearly as efficient).
Note that while our retail package came with a regular 5V 2A charger, the phone supports Quick Charge 3.0, which boosts charging speed from 10W to up to 18W. The battery is not removable, so quick top ups can save your bacon.
Both web browsing and video playback took 10 hours to drain the Zenfone's battery. That's better than, say, an LG V20 (3,200mAh), which lasted about 8 hours on both. A Huawei nova plus (3,340mAh) lasts 11:30 and 10:30 hours respectively, so in the same ballpark. The Samsung Galaxy C7 (both it and the nova use Snapdragon 625) went up to about 15 hours for both tests, really stretching its 3,300mAh battery, even with its bigger 5.7" screen.
The talk time is good though not stellar. More importantly, the Endurance rating came out to a good 74 hours - about as good as the Huawei nova plus, though not living up to Galaxy C7's 100 hours. It's better than the LG V20 flagship, though.
The battery testing procedure is described in detail in case you're interested in the nitty-gritties. You can also check out our complete battery test table, where you can see how all of the smartphones we've tested will compare under your own typical use.