| Hardware and OS | vivo X51 5G | Oppo A3s |
| Operating system | Android 10, Funtouch 10.0 | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | Octa-core (1x2.4 GHz Kryo 475 Prime & 1x2.2 GHz Kryo 475 Gold & 6x1.8 GHz Kryo 475 Silver) | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | Qualcomm SM7250 Snapdragon 765G 5G (7 nm) | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | Adreno 620 | Adreno 506 |
| Internal memory | 256GB 8GB RAM | 16 GB, 2 GB RAM |
| External memory | No | microSD, up to 256 GB (dedicated slot) |
| Display | vivo X51 5G | Oppo A3s |
| Type | AMOLED, 90Hz, HDR10 | IPS LCD |
| Size | 6.56 inches, 104.6 cm2 | 6.2" inc |
| Resolution | 1080 x 2376 pixels | 720 x 1520 px |
| Touchscreen | | capacitive touchscreen |
| Screen-to-Body Ratio | | 81.2% |
| Display area | | 95.9 cm2 |
| Display aspect ratio | | 19:9 (height:width) |
| Pixel Density | | 271 PPI |
| Colors | | 16M |
| Main Camera | vivo X51 5G | Oppo A3s |
| Features | Dual-LED dual-tone flash, HDR, panorama | |
| Video | 4K@30fps, 1080p@30fps, gyro-EIS | |
| Selfie camera | vivo X51 5G | Oppo A3s |
| Camera | 32 MP, f/2.5, 26mm (wide), 1/2.8", 0.8µm | |
| Features | HDR | |
| Video | 1080p@30fps | |
| Connectivity | vivo X51 5G | Oppo A3s |
| 2G Network | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100 | HSDPA 850 / 900 / 2100 |
| 4G Network | 1, 2, 3, 4, 5, 7, 8, 12, 17, 18, 19, 20, 26, 28, 32, 38, 39, 40, 41, 66 | LTE |
| Wi-Fi | | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| Network | | GSM / HSPA / LTE |
| 5G Network | 1, 3, 7, 8, 28, 38, 41, 77, 78 SA/NSA | |
| SIM card | | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | 5.1, A2DP, LE, aptX HD | 4.2, A2DP, LE |
| CDMA | CDMA 800 | |
| Edge | | Yes |
| GPRS | | Yes |
| NFC | Yes | |
| GPS | Yes, with A-GPS, GLONASS, GALILEO, BDS | Yes, with A-GPS |
| Speed | HSPA 42.2/5.76 Mbps, LTE-A, 5G | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| Technology | GSM / CDMA / HSPA / LTE / 5G | |
| USB | USB Type-C 2.0, USB On-The-Go | microUSB 2.0, USB On-The-Go |
| WLAN | Wi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi Direct, hotspot | |
| Camera | vivo X51 5G | Oppo A3s |
| Main camera | | 13 MP, Dual |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | | LED flash, HDR, panorama |
| Video | | 1080p@30fps |
| Selfie camera | | 8 MP, Single |
| Multimedia | vivo X51 5G | Oppo A3s |
| Loudspeaker | Yes | |
| Multimedia | 32-bit/192kHz audio | |
| 3.5 mm Jack | No | Yes |
| Radio | No | FM radio |
| Design | vivo X51 5G | Oppo A3s |
| Body build | Glass front, glass back, aluminum frame | |
| Colors | Gray | Red, Dark Purple |
| Dimensions | 158.5 x 72.8 x 8 mm (6.24 x 2.87 x 0.31 in) | 156.2 x 75.6 x 8.2 mm |
| Weight | 181.5 g (6.42 oz) | 168 g |
| SIM | Dual SIM (Nano-SIM, dual stand-by) | |
| Battery | vivo X51 5G | Oppo A3s |
| Type | Li-Po 4315 mAh, non-removable | |
| Charging | Fast charging 33W, 57% in 30 min (advertised) | |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Features | vivo X51 5G | Oppo A3s |
| Sensors | Fingerprint (under display, optical), accelerometer, gyro, proximity, compass, color spectrum | |
| Other | vivo X51 5G | Oppo A3s |
| Release date | | 2018, July |
| Sensors | | Accelerometer, proximity, compass |
