Oppo A31 vs Vivo Y91i
| Type | Touch | Touch |
| Dimensions | 131.90 x 65.54 x 8.03 mm | 155.11 x 75.09 x 8.28 mm |
| Weight | 135.00 g | 163.50 g |
| Display size | 4.50" | 6.22" |
| Display | Color / IPS TFT 16M colors 480 x 854 px (4.50") 218 ppi | Color / IPS TFT 16M colors 720 x 1520 px (6.22") 270 ppi |
| Display protection |   | |
| Additional display | | |
| Protection of the secondary display | | |
| Standard battery | Li-Ion 2000 mAhBuy powerbank
| Li-Ion 4030 mAhBuy powerbank
|
| Quick battery charging | | |
| Wireless battery charging | | |
| Internal memory | 8 GB | 32 GB |
| RAM memory | 1 GB | 3 GB |
| Memory cards |  microSD, microSDHC, microSDXC up to 128 GBBuy memory card |  |
| Operating system | Android 4.4 KitKat | Android 8.1 Oreo |
| Interface | ColorOS 2.0.1 | Funtouch 4.5 |
| Processor | Qualcomm Snapdragon 410 8916 | Qualcomm Snapdragon 439 |
| Processor clock | 1200 MHz | 1950 MHz |
| GPU | Adreno 306 | Adreno 505 |
| Touchscreen | | |
| DualSIM | | |
| SIM cards standard | DualSIM(microSIM, nanoSIM) | |
| Hybrid DualSIM | | nd |
| Announced | 2Q 2015 | 4Q 2018 |
| Other names | A31t | Vivo 1816 |
| GSM frequencies | 850 900 1800 1900 | 850 900 1800 1900 |
| UMTS | | 850 900 1900 2100 |
| LTE standard | TDD LTE: 2600, 2500, 2300, 1900 | |
| CDMA | | |
| Standard TD-SCDMA | 1900 2000 | |
| UMA | | |
CAMERAS - BACK
| First camera | | |
| Photo matrix | 8 Mpx | 13 Mpx |
| Resolution | 3264x2448 px | |
| Optical zoom | | |
| Flash | LED | LED |
| Dual-colour LED flash | | |
| Video resolution | 1920x1080 px | |
| Video formats | H.263, H.264, MPEG4 | MPEG4, H.263, H.264 |
| Additional | AF | - |
CAMERAS - FRONT
| First camera | | |
| Photo matrix | 2 Mpx | nd |
| Resolution | 1600x1200 px | nd |
| Optical zoom | | nd |
| Flash | | nd |
| Dual-colour LED flash | | nd |
| Video formats | H.263, H.264, MPEG4 | nd |
| Additional | FF | nd |
SENSORS
| Accelerometer | | |
| Proximity | | |
| Light | | |
| Magnetometer | | |
| Gyroscope | | |
| Barometer | | |
| Altimeter | | |
| Gravity | | |
| Hall-effect | | |
| Iris scanner | | |
| Fingerprint scanner | | |
| Thermometer | | |
| Hygrometer | | |
Data transfer
| xHTML | | |
| WAP | v2.0 | v2.0 |
| HSCSD | | |
| HSDPA | 42.00 Mbit/s | |
| HSUPA | 5.76 Mbit/s | |
| HSPA | | |
| HSPA+ | | |
| LTE DL | | |
| LTE UP | | |
| WIMAX+ | | |
| GPRS | class 12 | |
| EDGE | | |
| Bluetooth | v4.0 | v4.2 |
| A2DP Profile | | |
| HDMI | | |
| WiFi | v802.11 b/g/n | v802.11 b/g/n |
| WiFi frequencies | 2,4 GHz | 2,4 GHz |
| WiFi Direct | | |
| WiFi Display | | |
| DLNA | | |
| Miracast | | |
| WiFi hotspot | | |
| IrDA | | |
| USB | v2.0 | v2.0 |
| GPS | | |
| A-GPS | | |
| GLONASS | | |
| Beidou | | |
| Galileo | | |
| QZSS | | |
| NFC | | |
COMMUNICATION AND MESSAGING
| Call waiting | | |
| Conferency | | |
| Call forwarding | | |
| Push To Talk | | |
| Instant Messenger | | |
| SMS | | |
| EMS | | |
| MMS | | |
| Dictionary | XT9 | XT9 |
| Swype | | |
| e-mail client | POP3, IMAP4, SMTP | POP3, IMAP4, SMTP |
| Hardware QWERTY keyboard | | |
| RSS Reader | | |
Multimedia
| Radio | | |
| MP3 | | |
| Stereo speakers | | |
| Audio Jack | 3.5 mm | 3.5 mm |
| HD Voice | | |
| Sound formats | AAC, AAC+, APE, FLAC, MKA, OGG, WAV, eAAC+ | AMR, APE, FLAC, MIDI, WAV |
| Polyphony | 64 voices | |
| Video ringtone | | |
| Ring composer | | |
| Games | | |
| Java | Dalvik | ART |
| Videophone | | |
| DVB-H television | | |
| TV-Out | | |
PIM AND ADDITIONAL FUNCTIONS
| Watch | | |
| Stopwatch | | |
| Alarm | | |
| Calculator | | |
| Currency converter | | |
| Organizer | | |
| Calendar | | |
| Flight mode | | |
| SyncML | | |
| Data and fax | | |
| Screensaver | | |
| Themes | | |
| Interchangeable covers | | |
| Voice dial | | |
| Speakerphone | | |
| Recorder | | |
| Vibrations | | |