Oppo A3 vs Vivo X21
| Type | Touch | Touch |
| Dimensions | 156.00 x 75.30 x 7.80 mm | 154.45 x 74.78 x 7.37 mm |
| Weight | 159.00 g | 156.20 g |
| Display size | 6.20" | 6.28" |
| Display | Color / IPS TFT 16M colors 1080 x 2280 px (6.20") 407 ppi | Color / Super AMOLED 16M colors 1080 x 2280 px (6.28") 402 ppi |
| Display protection |   | Corning Gorilla Glass Buy screen protector
|
| Additional display | | |
| Protection of the secondary display | | |
| Standard battery | Li-Ion 3400 mAhBuy powerbank
| Li-Ion 3200 mAhBuy powerbank
|
| Quick battery charging | | |
| Wireless battery charging | | |
| Internal memory | 64 GB, 128 GB | 64 GB, 128 GB |
| RAM memory | 4 GB, 6 GB | 6 GB |
| Memory cards |  microSD, microSDHC, microSDXC up to 256 GBBuy memory card | microSD, microSDHC, microSDXC up to 256 GBBuy memory card |
| Operating system | Android 8.1 Oreo | Android 8.1 Oreo |
| Interface | ColorOS 5.0 | Funtouch 4.0 |
| Processor | MediaTek Helio P60 MT6771 | Qualcomm Snapdragon 660 |
| Processor clock | 2000 MHz | 2200 MHz |
| GPU | ARM Mali-G72 MP3 @800 MHz | Adreno 512 |
| Touchscreen | | |
| DualSIM | | |
| SIM cards standard | DualSIM(nanoSIM, nanoSIM) | DualSIM(nanoSIM, nanoSIM) |
| DualSIM mode | dual standby | dual standby |
| Hybrid DualSIM | |  |
| Announced | 2Q 2018 | 1Q 2018 |
| Other names | PADT00 | - |
| GSM frequencies | 850 900 1800 1900 | 850 900 1800 1900 |
| UMTS | 850 900 1900 2100 | 850 900 1900 2100 |
| LTE standard | FDD LTE: 2600, 2100, 1800, 1700, 900, 850 TDD LTE: 2600, 2500, 2300, 1900 | FDD LTE: 2100, 1900, 1800, 1700, 900, 850 TDD LTE: 2600, 2500, 2300, 2100, 1900 |
| CDMA | 850 CDMA2000 1xEV-DO | 850 |
| Standard TD-SCDMA | 1900 2000 | 1900 2000 |
| UMA | | |
CAMERAS - BACK
| First camera | | |
| Photo sensor model | | Samsung S5K2L9 |
| Photo matrix | 16 Mpx | 12 Mpx |
| Resolution | 4608x3456 px | 4016x3008 px |
| Optical zoom | | |
| Flash | | LED |
| Dual-colour LED flash | | |
| Video resolution | 1920x1080 px | |
| Video formats | H.263, H.264, MPEG4 - 30 fps | H.263, H.264, MPEG4 - 30 fps |
| Additional | AF, f/1.8 | AF, f/1.8 |
| Second camera | | |
| Photo sensor model | nd | Samsung S5K4E8 |
| Photo matrix | nd | 5 Mpx |
| Resolution | nd | 2592x1944 px |
| Optical zoom | nd | |
| Flash | nd | LED |
| Dual-colour LED flash | nd | |
| Video formats | nd | H.263, H.264, MPEG4 - 30 fps |
| Additional | nd | FF, f/2.4 |
CAMERAS - FRONT
| First camera | | |
| Photo sensor model | | Samsung S5K2L8 |
| Photo matrix | 8 Mpx | 12 Mpx |
| Resolution | 3264x2448 px | 4016x3008 px |
| Optical zoom | | |
| Flash | | |
| Dual-colour LED flash | | |
| Video formats | H.263, H.264, MPEG4 - 30 fps | H.263, H.264, MPEG4 - 30 fps |
| Additional | FF, f/2.2 | FF, f/2.0 |
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 | 42.20 Mbit/s |
| HSUPA | 5.76 Mbit/s | 5.76 Mbit/s |
| HSPA | | |
| HSPA+ | | |
| LTE DL | - | |
| LTE UP | - | |
| WIMAX+ | | |
| GPRS | | |
| EDGE | | |
| Bluetooth | v4.2 | v5.0 |
| A2DP Profile | | |
| HDMI | | |
| WiFi | v802.11 a/b/g/n/ac | v802.11 a/b/g/n/ac |
| WiFi frequencies | 2,4 GHz; 5 GHz | 2,4 GHz; 5 GHz |
| WiFi Direct | | |
| WiFi Display | | |
| 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 | T9 | |
| 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, OGG, WAV, WMA, eAAC+ | AAC, AAC+, AMR, APE, FLAC, MID, OGG, WAV, eAAC+ |
| 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 | | |