In depth comparison and review of Xiaomi Redmi Note 9 and Microsoft Surface Duo 2. Compare sizes, cameras, batteries, memory, and other important specifications and features to easily choose the right phone for you. Our goal is to help you uncover differences between the products and find the phone that will best fit your needs.
| DESIGN AND DIMENSIONS | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Product Type | Smartphone | Smartphone | |
|---|---|---|---|
| Form Factor | Touch | Folder - dual screen | |
| Height | 162.3 mm | 145.2 mm | Xiaomi Redmi Note 9 has greater height than Microsoft Surface Duo 2. |
| Width | 77.2 mm | 92.1 mm | Microsoft Surface Duo 2 has greater width than Xiaomi Redmi Note 9. |
| Depth | 8.9 mm | 11 mm | Xiaomi Redmi Note 9 is narrower than Xiaomi Redmi Note 9. |
| Weight | 199 g | 284 g | Xiaomi Redmi Note 9 is lighter than Xiaomi Redmi Note 9. |
| Dimensions Details | - | Unfolded - 184.5 mm x 5.5 mm x 145.2 mm | |
| Body Colour | Forest green | Glacier | Obsidian | |
| Body Material | - | Corning Gorilla Glass | |
| Protection | Splashproof | - | |
| Waterproof (Water-resistant) | - | - | |
| Repairability Index | - | 3.9 (out of 10) | |
| SAR Value | 2.262 W/kg (limb), 1.138 W/kg (body), 0.795 W/kg (head) | 0.726 W/kg (head), 1.478 W/kg (body) | |
| Integrated Components | Ultra-linear speaker | - | |
| Connector Type | USB Type-C - 24 pin USB-C Headset jack - mini-phone 3.5mm |
USB Type-C - 24 pin USB-C | |
| SIM Card Type (Size) | Nano SIM | Nano SIM, Electronic SIM card (e-SIM) | |
| SIM Card Qty | Dual-SIM | Dual-SIM | |
| SIM Card Configuration Details | Nano SIM + nano SIM/microSD | - |
| DISPLAY | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Display Type | - | OLED display | |
|---|---|---|---|
| Display Technology | - | AMOLED | |
| Foldable Display | - | Yes | |
| Display Design | - | Both directions folding | |
| Screen Size (Display Size) | 6.53" | 5.8" | Xiaomi Redmi Note 9 has larger screen size than Microsoft Surface Duo 2. |
| Screen Resolution (Display Resolution) | 2340 x 1080 pixels | 1344 x 1892 pixels | Microsoft Surface Duo 2 has better screen resolution than Xiaomi Redmi Note 9. |
| Display Format | Full HD+ | - | |
| Pixel Density | - | 401 ppi | |
| Aspect Ratio | 19.5:9 | 13:9 | |
| Max Brightness | 450 cd/m² | 800 cd/m² | Microsoft Surface Duo 2 has better display brightness than Xiaomi Redmi Note 9. |
| Contrast Ratio | 1500:1 | - | |
| HDR | - | Yes | Microsoft Surface Duo 2 has HDR. |
| Display Refresh Rate | - | 90 Hz | |
| Display Features | Reading mode 2.0, Dot Display, Full Screen gestures | DCI-P3 Wide colour gamut, 100% sRGB, Dual PixelSense Fusion Displays | |
| Display Protection (Screen Protector) | Corning Gorilla Glass 5 (scratch resistant glass) | Corning Gorilla Glass Victus (scratch resistant glass) |
| SECOND DISPLAY |
|---|
| Second Display Type | - | OLED display - colour | |
|---|---|---|---|
| Second Display Screen Size | - | 5.8" | |
| Second Display Resolution | - | 1344 x 1892 pixels |
| UNFOLDED DISPLAY |
|---|
| Unfolded Display Screen Size | - | 8.3 in | |
|---|---|---|---|
| Unfolded Display Resolution | - | 2688 x 1892 pixels |
| PROCESSOR | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Processor Type (CPU) | MediaTek Helio G85 | Qualcomm Snapdragon 888 5G | |
|---|---|---|---|
| Clock Speed | 2 GHz | - | |
| Processor Core Qty | 8-core | 8-core | Both phones have the same number of phone cores. |
| Graphics System (GPU) | ARM G52 MC2 | - |
| MEMORY | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| RAM | 3 GB | LPDDR5 SDRAM - 8 GB | Microsoft Surface Duo 2 has more RAM than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Internal Memory Size (Storage Capacity) | 64 GB | 128 GB | Microsoft Surface Duo 2 has more internal memory than Xiaomi Redmi Note 9. |
| Supported Flash Memory Cards (Expandable Memory) | microSD | - |
| CAMERA | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| MAIN CAMERA |
|---|
| Number of Main Cameras | 4 | 3 | |
|---|---|---|---|
| Sensor Resolution | 48 Megapixel | 12 Megapixel | Xiaomi Redmi Note 9 has better camera resolution than Microsoft Surface Duo 2. |
| Sensor Size | 1/2" | - | |
| Lens Aperture | F/1.79 | F/1.7 | Microsoft Surface Duo 2 has better lens aperture than Xiaomi Redmi Note 9. |
| Lens Construction | 6-element | - | |
| Field of View (FoV) | 79.4 degree(s) | - | |
| Pixel Size | 0.8 μm | 1.4 μm | Microsoft Surface Duo 2 has larger camera pixel size than Xiaomi Redmi Note 9. |
| Optical Image Stabiliser (OIS) | - | Optical Image Stabiliser (OIS) | Microsoft Surface Duo 2 has optical stabilisation. |
| Focus Adjustment | Automatic | - | |
| Digital Zoom | - | 10x | |
| Special Effects | HDR, Kaleidoscope | HDR | |
| Camera Modes | Burst mode, Panorama, night mode, Smart ultra-wide angle mode, Photo timer, Custom watermark, Documents, Beautify, Levelling, Cinematic portraits | Night mode, Auto mode, low-light shots, Panorama mode with wide dynamic range, slow motion video at 120 or 240fps | |
| Face Recognition (Face ID) | Face recognition | - | Xiaomi Redmi Note 9 has face detection. |
| Light Source | Flash | Dual LED flash | |
| Video Resolutions | 1920 x 1080 (1080p) at 30 fps, 1280 x 720 (720p) at 30 fps, Slo-mo video 1280 x 720 (720p) at 120 fps | 1920 x 1080 (1080p) at 30 fps, 1920 x 1080 (1080p) at 60 fps, 3840 x 2160 (4K) at 30 fps, 3840 x 2160 (4K) at 60 fps | |
| Camera Features (Functions) | 4-in-1 Super Pixel, AI scene detection, Portrait mode with background blurring, Ultra wide-angle edge distortion correction, Steady handheld night photography, full screen frame, AI watermark | Dual Pixel Phase Detect Auto-Focus (PDAF), Smooth Zoom, HEVC (High Efficiency Video coding), HDR video recording, multi-frame photo capture, dynamic range scene detection |
| SECOND CAMERA |
|---|
| Sensor Resolution (2nd Camera) | 8 Megapixel | 12 Megapixel | Microsoft Surface Duo 2 has better second camera resolution than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Sensor Size (2nd Camera) | 1/4" | - | |
| Lens Type (2nd Camera) | Ultra wide-angle lens | Telephoto lens | |
| Lens Aperture (2nd Camera) | F/2.2 | F/2.4 | Xiaomi Redmi Note 9 has better second camera lens aperture than Xiaomi Redmi Note 9. |
| Lens Element Qty (2nd Camera) | 5-element | - | |
| Field of View (2nd Camera) | 118 degree(s) | - | |
| Pixel Size (2nd Camera) | 1.2 μm | 1 μm | Xiaomi Redmi Note 9 has larger second camera pixel size than Microsoft Surface Duo 2. |
| Optical Image Stabiliser (OIS) | - | Optical Image Stabiliser (OIS) | Microsoft Surface Duo 2 has optical stabilisation of the second camera. |
| Optical Zoom | - | 2x | |
| Camera Features (2nd Camera) | 5-piece lens | Phase Detect Auto-Focus (PDAF) |
| THIRD CAMERA |
|---|
| Sensor Resolution (3rd Camera) | 2 Megapixel | 16 Megapixel | Microsoft Surface Duo 2 has higher resolution third camera than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Lens Type (3rd Camera) | - | Ultra wide-angle lens | |
| Lens Aperture (3rd Camera) | F/2.4 | F/2.2 | Microsoft Surface Duo 2 has better third camera lens aperture than Xiaomi Redmi Note 9. |
| Field of View (3rd Camera) | - | 110 degree(s) | |
| Pixel Size (3rd Camera) | 1.75 μm | 1 μm | Xiaomi Redmi Note 9 has larger third camera pixel size than Microsoft Surface Duo 2. |
| Camera Functions (3rd Camera) | Macro camera | - | |
| Camera Features (3rd Camera) | AF (2cm-10cm) | Field of view, distortion correction |
| FOURTH CAMERA |
|---|
| Sensor Resolution (4th Camera) | 2 Megapixel | - | |
|---|---|---|---|
| Sensor Size (4th Camera) | 1/5" | - | |
| Lens Aperture (4th Camera) | F/2.4 | - | |
| Lens Element Qty (4th Camera) | 3-element | - | |
| Pixel Size (4th Camera) | 1.75 μm | - | |
| Camera Functions (4th Camera) | Depth camera | - |
| FRONT CAMERA |
|---|
| Number of Front Cameras | 1 | 1 | |
|---|---|---|---|
| Sensor Resolution (Front) | 13 Megapixel | 12 Megapixel | Xiaomi Redmi Note 9 has better front camera resolution than Microsoft Surface Duo 2. |
| Sensor Size (Front) | 1/3.06" | - | |
| Lens Aperture (Front) | F/2.25 | F/2.0 | Microsoft Surface Duo 2 has better front lens aperture than Xiaomi Redmi Note 9. |
| Lens Element Qty (Front) | 5-element | - | |
| Field of View (Front) | 74 degree(s) | - | |
| Pixel Size (Front) | 1.12 μm | 1 μm | Xiaomi Redmi Note 9 has larger front camera pixel size than Microsoft Surface Duo 2. |
| Special Effects (Front) | HDR | - | |
| Camera Modes (Front) | Panoramic selfies, AI portrait mode, AI Beautify | - | |
| Face Recognition (Face ID) | Face recognition | - | Xiaomi Redmi Note 9 has face detection. |
| Light Source (Front) | Display flash | - | |
| Camera Features (Front) | Palm shutter, AI silhouette detection | - |
| BATTERY AND CHARGING | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Battery Capacity (Battery Size) | 5020 mAh | 4449 mAh | Xiaomi Redmi Note 9 has larger battery capacity than Microsoft Surface Duo 2. |
|---|---|---|---|
| Talk Time | 1980 minutes | 1680 minutes | Xiaomi Redmi Note 9 has longer battery life when making calls than Microsoft Surface Duo 2. |
| Run Time Details | Talk: up to 1980 min Gaming: up to 16 hrs Playback (Music): up to 147 hrs Navigation: up to 16 hrs |
Talk: up to 1680 min Playback (local video): up to 15.5 hrs |
|
| Battery Technology | Lithium polymer | - |
| CELLULAR | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Technology | WCDMA (UMTS) / GSM | WCDMA (UMTS) / GSM | |
|---|---|---|---|
| Mobile Broadband Generation | 4G | 5G | Microsoft Surface Duo 2 has more advanced generation mobile network. |
| Operating System | - | Android 11 | |
| Intelligent Assistant | - | Google Assistant | |
| Navigation | GPS, A-GPS, GLONASS, BeiDou, Galileo | GPS, GLONASS, BeiDou, Galileo, QZSS |
| COMMUNICATIONS | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Data Transmission | VoLTE, FDD-LTE, TDD-LTE | GPRS, FDD-LTE, TDD-LTE, Gigabit LTE, LAA, 5G NR FR1 | |
|---|---|---|---|
| 2G Band | 850 GSM, 900 GSM, 1900 GSM, 2100 GSM | 850 GSM, 900 GSM, 1800 GSM, 1900 GSM | |
| 3G UMTS Band | Band 1, Band 2, Band 4, Band 5, Band 8 | Band 1, Band 2, Band 5, Band 8 | |
| 3G UMTS Frequency | 2100, 1900, 1700, 850, 900 | 2100, 1900, 850, 900 | |
| 4G LTE Band | Band 1, Band 2, Band 3, Band 4, Band 5, Band 7, Band 8, Band 20, Band 28, Band 38, Band 40, Band 41 | Band 1, Band 2, Band 3, Band 4, Band 5, Band 7, Band 8, Band 12, Band 13, Band 14, Band 19, Band 20, Band 25, Band 26, Band 28, Band 29, Band 30, Band 38, Band 39, Band 40, Band 41, Band 42, Band 46, Band 48, Band 66, Band 71 | |
| 4G LTE Frequency | FDD 2100, FDD 1900 PCS, FDD 1800+, FDD 1700 - 2110 AWS, FDD 850, FDD 2600, FDD 900, FDD 800 DD, FDD 700 APT, TDD 2600, TDD 2300, TDD 2500 | FDD 2100, FDD 1900 PCS, FDD 1800+, FDD 1700 - 2110 AWS, FDD 850, FDD 2600, FDD 900, FDD 700a, FDD 700c, FDD 700 PS, FDD 800 upper, FDD 800 DD, FDD 1900+, FDD 850+, FDD 700 APT, FDD 700d, FDD 2300 WCS, TDD 2600, TDD 1900, TDD 2300, TDD 2500, TDD 3500, TDD 5150, TDD 3600, FDD 1700 - 2110 AWS-3, FDD 600 | |
| 5G NR Band | - | N1, n2, n3, n5, n7, n20, n28, n38, n41, n66, n71, n77, n78, n79, n25 | |
| 5G NR Frequency | - | FDD 2100, FDD 1900PCS, FDD 1800, FDD 850, FDD 2600, FDD 800, FDD 700APT, TDD TD 2600, TDD TD 2500, FDD AWS-3, FDD 600, TDD TD 3700, TDD TD 3500, TDD TD 4500, FDD 1900 | |
| Wireless Interface | IEEE 802.11a/b/g/n/ac | IEEE 802.11ax | |
| Bluetooth | Bluetooth 5.0 | Bluetooth 5.1 | |
| NFC | - | Yes | Microsoft Surface Duo 2 has NFC reader for mobile payments. |
| MEDIA | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Supported Digital Audio Standards | WAV, AAC, AMR, MP3, FLAC, APE (Monkey's Audio) | WAV, AAC, AMR, MP3, FLAC, OGG, MIDI, M4A, apt-X, IMY, RTX, OTA, MID, TWS, RTTL | |
|---|---|---|---|
| Supported Digital Video Standards | MKV, XviD, M4V, MP4 | MKV, FLV, AVI, MOV, MPEG-4, WMV, ASF, 3GP, H.264, TS, M2TS, WebM, HEVC, 3G2, HEIF, H.265 HEVC, HEIC | |
| Sound Enhancements | - | Qualcomm aptX HD audio, Qualcomm aptX Classic | |
| Audio Amplifier | Smart PA | - |
| FEATURES | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Phone Functions | Speakerphone, voice control, call timer, conference call, flight mode, voice dialing, vibrating alert | Speakerphone, voice control, call timer, conference call, flight mode, voice dialing, vibrating alert | |
|---|---|---|---|
| Sensors | Accelerometer, ambient light sensor, proximity sensor, digital compass, gyro sensor, infrared (IR) sensor | Hall sensor, Time of Flight (ToF), dual accelerometers, dual gyroscope, dual magnetometer, dual ambient light sensor, dual proximity sensor | |
| Security Devices | Face recognition, fingerprint reader | Fingerprint reader (side) | |
| Additional Phone Features | Infrared remote control, HyperEngine technology | MIMO technology, Fast Charging, dual battery, Full Duplex communication, dual microphones with AI-based noise suppression and acoustic echo cancellation |
| OTHERS | Xiaomi Redmi Note 9 | Microsoft Surface Duo 2 |
|---|
| Included Accessories | Protective cover, power adapter, SIM card removal tool, USB-C cable | SIM card removal tool, USB-C headset, Surface Duo 2 USB-C cable | |
|---|---|---|---|
| Compliant Standards | TUV Rheinland Low Blue Light Certification | HEARING AID M4/T3 |
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