| Hardware and OS | Redmi Note 5A (S) | Oppo A3s |
| Operating system | Android 7.1.1 (Nougat) | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| RAM | 2GB, 3GB, 4GB | |
| GPU | Adreno 308, Adreno 505 | Adreno 506 |
| Internal Storage | 16GB, 32GB, 64GB | |
| Internal memory | | 16 GB, 2 GB RAM |
| Memory Card Slot | Yes (up to 128GB) | |
| External memory | | microSD, up to 256 GB (dedicated slot) |
| User Interface | MIUI 9.0 | |
| Display | Redmi Note 5A (S) | Oppo A3s |
| Type | IPS | IPS LCD |
| Size | 5.5 inch | 6.2" inc |
| Resolution | 1280 x 720 (HD) | 720 x 1520 px |
| Touchscreen | Yes | capacitive touchscreen |
| Screen-to-Body Ratio | | 81.2% |
| Display area | | 95.9 cm2 |
| Display aspect ratio | | 19:9 (height:width) |
| Features | Eye Protection Mode, Color Temperature Adjustment | |
| Pixel Density | 267 ppi | 271 PPI |
| Colors | 16 Million Colors, 70% NTSC, 1000:1 Contrast Ratio, 450nits | 16M |
| Connectivity | Redmi Note 5A (S) | Oppo A3s |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| NFC | No | |
| 3G Network | | HSDPA 850 / 900 / 2100 |
| 4G Network | | LTE |
| Wi-Fi | Wi-Fi 802.11 b/g/n, Single Band, Wi-Fi Direct | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| SIM | Nano SIM | |
| Network | | GSM / HSPA / LTE |
| Dual SIM | Yes (With Non-Hybrid MicroSD Expansion) | |
| SIM card | | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | | 4.2, A2DP, LE |
| Edge | | Yes |
| GPRS | | Yes |
| GPS | Yes - GPS/ AGPS/ Glonass/ BDS | Yes, with A-GPS |
| Speed | HSPA, LTE | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB | MicroUSB 2.0 (w/ USB Host) | microUSB 2.0, USB On-The-Go |
| Camera | Redmi Note 5A (S) | Oppo A3s |
| Main camera | 13MP, f/2.2 | 13 MP, Dual |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | LED Flash | LED flash, HDR, panorama |
| Video | | 1080p@30fps |
| Selfie camera | 16 MP, f/2.0 | 8 MP, Single |
| Multimedia | Redmi Note 5A (S) | Oppo A3s |
| Loudspeaker | Yes | |
| Video Playback | MP4, M4V, MKV, XVID, WAV, AAC (H.265 Support) | |
| 3.5 mm Jack | yes | Yes |
| Radio | | FM radio |
| Design | Redmi Note 5A (S) | Oppo A3s |
| Waterproof | No | |
| Colors | | Red, Dark Purple |
| Dimensions | 153 x 76.2 x 7.55 mm | 156.2 x 75.6 x 8.2 mm |
| Weight | 150g | 168 g |
| Battery | Redmi Note 5A (S) | Oppo A3s |
| Placement | Non-Removable | |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Other | Redmi Note 5A (S) | Oppo A3s |
| Release date | | 2018, July |
| Sensors | Fingerprint Sensor (Rear), Accelerometer, Proximity Sensor, Ambient Light Sensor, Magnetometer, Vibration Motor, Infra-red Sensor | Accelerometer, proximity, compass |
