| Hardware and OS | Xiaomi Redmi K40 Ultra | Oppo A3s |
| Operating system | Android v11 | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | 3 GHz, Octa Core Processor | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | MediaTek Dimensity 1200 | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | | Adreno 506 |
| Cores | 1x3.0 GHz Cortex-A78 & 3x2.6 GHz Cortex-A78 & 4x2.0 GHz Cortex-A55 | |
| Internal memory | 128 GB | 16 GB, 2 GB RAM |
| RAM | 8 GB | |
| External memory | | microSD, up to 256 GB (dedicated slot) |
| Memory Card Slot | No | |
| Graphics | Mali-G77 MC9 | |
| Dual Sim | Yes | |
| Sim Size | Nano Nano SIM | |
| Sim Type | Dual Sim, GSM GSM | |
| Display | Xiaomi Redmi K40 Ultra | Oppo A3s |
| Type | | IPS LCD |
| Size | | 6.2" inc |
| Resolution | | 720 x 1520 px |
| Touchscreen | | capacitive touchscreen |
| Screen-to-Body Ratio | ~ 86.3% | 81.2% |
| Display area | | 95.9 cm2 |
| Screen Size | 6.67 inches, 1080 x 2400 pixels, 120 Hz | |
| Display aspect ratio | 20:9 | 19:9 (height:width) |
| Display Type | Color OLED screen (16M) | |
| Pixel Density | ~395 PPI | 271 PPI |
| Colors | | 16M |
| Touch Screen | Yes, with Multitouch | |
| Connectivity | Xiaomi Redmi K40 Ultra | Oppo A3s |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | Yes | HSDPA 850 / 900 / 2100 |
| 4G Network | Yes | LTE |
| Wi-Fi | | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| Network | | GSM / HSPA / LTE |
| 5G Network | Yes | |
| SIM card | | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | Yes, v5.2 | 4.2, A2DP, LE |
| Edge | Yes | Yes |
| GPRS | Yes | Yes |
| GPS | | Yes, with A-GPS |
| USB Features | USB Tethering, USB on-the-go, USB Charging | |
| Speed | | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| VoLTE | Yes, Dual Stand-By | |
| USB | Yes, USB-C | microUSB 2.0, USB On-The-Go |
| Wifi | Yes, with wifi-hotspot | |
| Camera | Xiaomi Redmi K40 Ultra | 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 | Xiaomi Redmi K40 Ultra | Oppo A3s |
| Email | Yes | |
| FM Radio | Yes | |
| Music | Yes | |
| Video | Yes | |
| Browser | Yes | |
| Java | No | |
| 3.5 mm Jack | | Yes |
| Radio | | FM radio |
| Design | Xiaomi Redmi K40 Ultra | Oppo A3s |
| Colors | | Red, Dark Purple |
| Dimensions | | 156.2 x 75.6 x 8.2 mm |
| Weight | | 168 g |
| Battery | Xiaomi Redmi K40 Ultra | Oppo A3s |
| Type | Non-Removable Battery | |
| Fast Charging | 67W Fast Charging | |
| Battery capacity | 5065 mAh, Li-Po Battery | 4230 mAh, Non-removable Li-Ion |
| Other | Xiaomi Redmi K40 Ultra | Oppo A3s |
| Fingerprint Sensor | Yes, In Display | |
| Face Unlock | Yes | |
| Dust Resistant | Yes | |
| Features | Digital Zoom, Auto Flash, Face detection, Touch to focus | |
| Release date | | 2018, July |
| Sensors | | Accelerometer, proximity, compass |
