Vivo X21 vs Oppo R9
| Type | Touch | Touch |
| Dimensions | 154.45 x 74.78 x 7.37 mm | 151.80 x 74.30 x 6.60 mm |
| Weight | 156.20 g | 145.00 g |
| Display size | 6.28" | 5.50" |
| Display | Color / Super AMOLED 16M colors 1080 x 2280 px (6.28") 402 ppi | Color / AMOLED 16M colors 1080 x 1920 px (5.50") 401 ppi |
| Display protection | Corning Gorilla Glass Buy screen protector
 | Corning Gorilla Glass Buy screen protector
|
| Additional display |  | |
| Protection of the secondary display | | |
| Standard battery | Li-Ion 3200 mAhBuy powerbank
| Li-Po 2850 mAhBuy powerbank
|
| Quick battery charging | | VOOC |
| Wireless battery charging | | Qi |
| Internal memory | 64 GB, 128 GB | 64 GB |
| RAM memory | 6 GB | 4 GB |
| Memory cards |  microSD, microSDHC, microSDXC up to 256 GBBuy memory card | microSD, microSDHC, microSDXC up to 128 GBBuy memory card |
| Operating system | Android 8.1 Oreo | Android 5.1 Lollipop |
| Interface | Funtouch 4.0 | ColorOS 3.0 |
| Processor | Qualcomm Snapdragon 660 | MediaTek Helio P10 MT6755 |
| Processor clock | 2200 MHz | 2000 MHz |
| GPU | Adreno 512 | ARM Mali-T860 MP2 @700 MHz |
| Touchscreen | | |
| DualSIM | | |
| SIM cards standard | DualSIM(nanoSIM, nanoSIM) | DualSIM(nanoSIM, nanoSIM) |
| DualSIM mode | dual standby | dual standby |
| Hybrid DualSIM |  | nanoSIM, microSD |
| Announced | 1Q 2018 | 1Q 2016 |
| Other names | - | - |
| GSM frequencies | 850 900 1800 1900 | 850 900 1800 1900 |
| UMTS | 850 900 1900 2100 | 850 900 1900 2100 |
| LTE standard | FDD LTE: 2100, 1900, 1800, 1700, 900, 850 TDD LTE: 2600, 2500, 2300, 2100, 1900 | FDD LTE: 2100, 1800, 850 TDD LTE: 2600, 2500, 2300, 1900 |
| CDMA | 850 | CDMA2000 1X |
| Standard TD-SCDMA | 1900 2000 | 1900 2000 |
| UMA | | |
CAMERAS - BACK
| First camera | | |
| Photo sensor model | Samsung S5K2L9 | |
| Photo matrix | 12 Mpx | 16 Mpx |
| Resolution | 4016x3008 px | 4608x3456 px |
| Optical zoom | | |
| Flash | LED | LED |
| Dual-colour LED flash | | |
| Video resolution | | 1920x1080 px |
| Video formats | H.263, H.264, MPEG4 - 30 fps | MPEG4, H.263, H.264 |
| Additional | AF, f/1.8 | AF, EIS, f/2.0 |
| Second camera | | |
| Photo sensor model | Samsung S5K4E8 | nd |
| Photo matrix | 5 Mpx | nd |
| Resolution | 2592x1944 px | nd |
| Optical zoom | | nd |
| Flash | LED | nd |
| Dual-colour LED flash | | nd |
| Video formats | H.263, H.264, MPEG4 - 30 fps | nd |
| Additional | FF, f/2.4 | nd |
CAMERAS - FRONT
| First camera | | |
| Photo sensor model | Samsung S5K2L8 | |
| Photo matrix | 12 Mpx | 13 Mpx |
| Resolution | 4016x3008 px | 4128x3096 px |
| Optical zoom | | |
| Flash | | |
| Dual-colour LED flash | | |
| Video formats | H.263, H.264, MPEG4 - 30 fps | MPEG4, H.263, H.264 |
| Additional | FF, f/2.0 | f/2.2 |
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 | 42.20 Mbit/s | 42.20 Mbit/s |
| HSUPA | 5.76 Mbit/s | 5.76 Mbit/s |
| HSPA | | |
| HSPA+ | | |
| LTE DL | | |
| LTE UP | | |
| WIMAX+ | | |
| GPRS | | |
| EDGE | | |
| Bluetooth | v5.0 | v4.0 |
| A2DP Profile | | |
| HDMI | | |
| WiFi | v802.11 a/b/g/n/ac | v802.11 a/b/g/n |
| WiFi frequencies | 2,4 GHz; 5 GHz | 2,4 GHz; 5 GHz |
| WiFi Direct | | |
| WiFi Display | | |
| DLNA | | |
| Miracast | | |
| WiFi hotspot | | |
| IrDA | | |
| USB | v2.0 | v2.0 |
| GPS | | |
| A-GPS | | |
| GLONASS | | |
| Beidou | | |
| NFC | | |
COMMUNICATION AND MESSAGING
| Call waiting | | |
| Conferency | | |
| Call forwarding | | |
| Push To Talk | | |
| Instant Messenger | | |
| SMS | | |
| EMS | | |
| MMS | | |
| Dictionary | | 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+, AMR, APE, FLAC, MID, OGG, WAV, eAAC+ | AAC, AMR, APE, FLAC, MIDI, OGG, WAV, WMA |
| Polyphony | | |
| Video ringtone | | |
| Ring composer | | |
| Games | | |
| Java | ART | 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 | | |