We were pleasantly surprised to find out that the Oppo R9s features an AMOLED display. We've seen many 5.5" 1,080 x 1,920px displays (that works out to 401ppi pixel density), but mostly LCDs. We have a preference for AMOLED over LCD - usually, it means better contrast and sunlight legibility, vivid colors too. The display is guarded by scratch-resistant Gorilla Glass 5.
The screen is reasonably bright, we clocked it at 410 nits. We rarely put the screen to maximum brightness, so that's plenty in practice. The black levels weren't a perfect zero, we detected the faintest glow (0.032), but contrast is still amazing (around 13,000:1). This is faint enough that you won't see the glowing black characteristic of LCD displays (especially ones on a phone in this price range).
|Display test||100% brightness|
|Black, cd/m2||White, cd/m2|
The R9s display is slightly more reflective than the best AMOLEDs out there, and as a result, its sunlight legibility isn't as good. It's still comparable to the LG V20 and superior to the HTC 10, which makes it a very good display.
We noticed a slight contrast shift as we viewed the Oppo at different angles. Colors are barely affected, and the effect is barely noticeable.
Color accuracy is not perfect. Oppo provides no adjustable color modes for the screen and the default setup produced an average deltaE of 6.4 and a maximum of 10.2. We checked for an sRGB option in the Developer options but we didn't find one. We value sRGB because most photos on the Internet are intended for that color gamut. However, we have a noted interest in photography, the moment you slap on an image filter on your photo you can stop worrying about color gamuts.
These readings are not perfect, but are comparable to the ZTE Axon 7 (5.5" AMOLED, QHD), Xiaomi Redmi Pro (5.5" AMOLED, 1080p), Samsung Galaxy C7 (5.7" AMOLED, 1080p) and others.
The Oppo R9s is a dual-SIM phone that uses a Qualcomm chipset, which means excellent support for the variety of mobile wireless connectivity. This includes the several LTE flavors, GSM and CDMA. VoLTE is supported as well for improved audio quality.
Local connectivity is also well covered with Wi-Fi ac and Bluetooth 4.1 support, but note that there's no NFC.
The microUSB 2.0 port on the phone offers On-The-Go functionality for connecting accessories, something often overlooked these days.
The Oppo R9s is powered by a 3,010mAh battery (Li-Po) sealed inside its metal body. The phone supports the fast VOOC charging standard and is bundled with the right charger for it - 5V @ 4A = 20W. In our tests, it reached 64% charge (from 0%) in half an hour.
ColorOS 3.0 features a few power saving techniques that are enabled by default, so you may notice the phone often takes up the initiative of killing background apps for you. If that causes issues, you can exempt specific apps from this behavior. We found it too aggressive to our taste and had to disable it for a few apps (a minor note: we wish we had a way to do this from the app switcher, instead of having to go into the settings).
Update: We completed the battery tests and found the endurance is as good as expected - the 3,010mAh battery is stretched to 74 hours, matching the Asus Zenfone 3 and Huawei nova plus (its direct competitors). The talk time is over 25 hours, an excellent result. The web browser lasted 10 hours, matching the Zenfone 3 ZE552KL and beating the likes of the Pixel XL and Huawei P9 Plus (two phones with 5.5" AMOLED screens, QHD and 1080p respectively).
The video playback score is even more impressive - we got close to 16 hours of continuous video, which is a fantastic result. Very few phones top the R9s in this department - you could marathon a whole season of your favorite 45-minute TV show!