In depth comparison and review of Xiaomi MI 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 MI 9 | Microsoft Surface Duo 2 |
|---|
| Product Type | Smartphone | Smartphone | |
|---|---|---|---|
| Form Factor | Touch | Folder - dual screen | |
| Height | 157.5 mm | 145.2 mm | Xiaomi MI 9 has greater height than Microsoft Surface Duo 2. |
| Width | 74.67 mm | 92.1 mm | Microsoft Surface Duo 2 has greater width than Xiaomi MI 9. |
| Depth | 7.61 mm | 11 mm | Xiaomi MI 9 is narrower than Xiaomi MI 9. |
| Weight | 173 g | 284 g | Xiaomi MI 9 is lighter than Xiaomi MI 9. |
| Dimensions Details | - | Unfolded - 184.5 mm x 5.5 mm x 145.2 mm | |
| Body Colour | Ocean blue | Piano black | Glacier | Obsidian | |
| Body Material | Curved glass | Corning Gorilla Glass | |
| Waterproof (Water-resistant) | - | - | |
| Repairability Index | - | 3.9 (out of 10) | |
| SAR Value | 1.301 W/kg (body), 1.389 W/kg (head) | 0.726 W/kg (head), 1.478 W/kg (body) | |
| Connector Type | USB Type-C - 24 pin USB-C | 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 |
| DISPLAY | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| Display Type | OLED display | OLED display | |
|---|---|---|---|
| Display Technology | AMOLED | AMOLED | |
| Foldable Display | - | Yes | |
| Display Design | - | Both directions folding | |
| Screen Size (Display Size) | 6.39" | 5.8" | Xiaomi MI 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 MI 9. |
| Display Format | Full HD+ | - | |
| Pixel Density | 403 ppi | 401 ppi | Xiaomi MI 9 has better pixel density than Microsoft Surface Duo 2. |
| Aspect Ratio | - | 13:9 | |
| Max Brightness | 600 cd/m² | 800 cd/m² | Microsoft Surface Duo 2 has better display brightness than Xiaomi MI 9. |
| Contrast Ratio | 60000:1 | - | |
| HDR | Yes | Yes | Both phones have HDR. |
| HDR Technology | HDR10 | - | |
| Display Enhancement Technology | Sunshine mode 2.0 | - | |
| Display Refresh Rate | - | 90 Hz | |
| Display Features | Always-on display, Reading mode, Colour temperature adjustment, night mode, Wide Colour Gamut (WCG) | DCI-P3 Wide colour gamut, 100% sRGB, Dual PixelSense Fusion Displays | |
| Display Protection (Screen Protector) | Fingerprint-resistant coating, Corning Gorilla Glass 6 (scratch resistant glass), oil protective coating | 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 MI 9 | Microsoft Surface Duo 2 |
|---|
| Processor Type (CPU) | Qualcomm Snapdragon 855 | Qualcomm Snapdragon 888 5G | |
|---|---|---|---|
| Clock Speed | 2.84 GHz | - | |
| Processor Core Qty | 8-core | 8-core | Both phones have the same number of phone cores. |
| 64-bit Architecture | Yes | - | Xiaomi MI 9 has 64-bit architecture. |
| Graphics System (GPU) | Qualcomm ADRENO 640 | - |
| MEMORY | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| RAM | LPDDR4X SDRAM - 6 GB | LPDDR5 SDRAM - 8 GB | Microsoft Surface Duo 2 has more RAM than Xiaomi MI 9. |
|---|---|---|---|
| Internal Memory Size (Storage Capacity) | 64 GB | 128 GB | Microsoft Surface Duo 2 has more internal memory than Xiaomi MI 9. |
| CAMERA | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| MAIN CAMERA |
|---|
| Number of Main Cameras | 3 | 3 | |
|---|---|---|---|
| Sensor Resolution | 48 Megapixel | 12 Megapixel | Xiaomi MI 9 has better camera resolution than Microsoft Surface Duo 2. |
| Sensor Name | Sony Exmor RS IMX586 sensor | - | |
| Lens Type | Ultra wide-angle lens | - | |
| Lens Aperture | F/1.75 | F/1.7 | Microsoft Surface Duo 2 has better lens aperture than Xiaomi MI 9. |
| Pixel Size | 0.8 μm | 1.4 μm | Microsoft Surface Duo 2 has larger camera pixel size than Xiaomi MI 9. |
| Optical Image Stabiliser (OIS) | - | Optical Image Stabiliser (OIS) | Microsoft Surface Duo 2 has optical stabilisation. |
| Focus Adjustment | Automatic | - | |
| Laser Auto Focus | Yes | - | |
| Optical Zoom | 2x | - | |
| Digital Zoom | 10x | 10x | Both phones have the same digital zoom. |
| Special Effects | HDR | HDR | |
| Camera Modes | Burst mode, Panorama, portrait mode, AI Beautify, Smart ultra-wide angle mode, Ultra nightscape mode, Photo timer, Level display, Custom watermark, Full body portrait mode, Moon mode | 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 MI 9 has face detection. |
| Light Source | Dual flash | Dual LED flash | |
| Still Image Resolutions | 8000 x 6000 | - | |
| Video Resolutions | 1920 x 1080 (1080p) at 30 fps, 1920 x 1080 (1080p) at 60 fps, 1280 x 720 (720p) at 30 fps, Slo-mo video 1920 x 1080 (1080p) at 120 fps, Slo-mo video 1280 x 720 (720p) at 240 fps, 3840 x 2160 (4K) at 30 fps, Slo-mo video 1280 x 720 (720p) at 120 fps, 3840 x 2160 (4K) at 60 fps, Slo-mo video 1920 x 1080 (1080p) at 240 fps, Slo-mo video 1920 x 1080 (1080p) at 960 fps, Slo-mo video 1280 x 720 (720p) at 960 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) | Sapphire crystal lens cover, Phase Detect Auto-Focus (PDAF), Dynamic photos, video stabilisation, Contrast Auto-Focus, AI scene detection, AI studio lighting, Video Beautify, AI Triple camera, 960 fps Smart audio pairing, AI lens flare, AI high resolution photos, Portrait mode background blur adjustment, Ultra wide-angle edge distortion correction, Group photo face correction, Portrait mode background blurring, Motion tracking, Quick motion | 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) | 12 Megapixel | 12 Megapixel | Both phones have the same second camera resolution. |
|---|---|---|---|
| Lens Type (2nd Camera) | Telephoto lens | Telephoto lens | |
| Lens Aperture (2nd Camera) | F/2.2 | F/2.4 | Xiaomi MI 9 has better second camera lens aperture than Xiaomi MI 9. |
| Pixel Size (2nd Camera) | 1 μm | 1 μm | Both phones have the same second camera pixel size. |
| 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) | Macro photography | Phase Detect Auto-Focus (PDAF) |
| THIRD CAMERA |
|---|
| Sensor Resolution (3rd Camera) | 16 Megapixel | 16 Megapixel | Both phones have the same third camera resolution. |
|---|---|---|---|
| Lens Type (3rd Camera) | Ultra wide-angle lens | Ultra wide-angle lens | |
| Lens Aperture (3rd Camera) | F/2.2 | F/2.2 | Both phones have the same lens aperture of the third camera. |
| Field of View (3rd Camera) | - | 110 degree(s) | |
| Pixel Size (3rd Camera) | 1 μm | 1 μm | Both phones have the same third camera pixel size. |
| Camera Features (3rd Camera) | - | Field of view, distortion correction |
| FRONT CAMERA |
|---|
| Number of Front Cameras | 1 | 1 | |
|---|---|---|---|
| Sensor Resolution (Front) | 20 Megapixel | 12 Megapixel | Xiaomi MI 9 has better front camera resolution than Microsoft Surface Duo 2. |
| Lens Aperture (Front) | F/2.0 | F/2.0 | Both phones have the same front camera lens aperture. |
| Pixel Size (Front) | 0.9 μm | 1 μm | Microsoft Surface Duo 2 has larger front camera pixel size than Xiaomi MI 9. |
| Special Effects (Front) | HDR, Magic mirror | - | |
| Camera Modes (Front) | AI portrait mode, AI Beautify, AI makeup | - | |
| Face Recognition (Face ID) | Face recognition | - | Xiaomi MI 9 has face detection. |
| Video Resolutions (Front) | 1920 x 1080 (1080p) at 30 fps, 1280 x 720 (720p) at 30 fps | - | |
| Camera Features (Front) | Self-timer, age recognition, Video Beautify, AI scene detection, AI studio lighting, Eye light, AI feature adjustment, AI lens flare | - |
| BATTERY AND CHARGING | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| Battery Capacity (Battery Size) | 3300 mAh | 4449 mAh | Microsoft Surface Duo 2 has larger battery capacity than Xiaomi MI 9. |
|---|---|---|---|
| Fast Charging Technology | Qualcomm Quick Charge 4.0+ | - | Xiaomi MI 9 has fast charging technology. |
| Wireless Charging Standards | WPC, Qi | - | |
| Talk Time | - | 1680 minutes | |
| Run Time Details | - | Talk: up to 1680 min Playback (local video): up to 15.5 hrs |
| CELLULAR | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| Technology | CDMA2000 1X / GSM / WCDMA (UMTS) / TD-SCDMA | WCDMA (UMTS) / GSM | |
|---|---|---|---|
| Mobile Broadband Generation | 4G | 5G | Microsoft Surface Duo 2 has more advanced generation mobile network. |
| Operating System | - | Android 11 | |
| User Interface | MIUI 10 | - | |
| Intelligent Assistant | Google Assistant | Google Assistant | |
| Payment Technology | Android Pay | - | |
| Navigation | GPS, A-GPS, GLONASS, BeiDou, Galileo | GPS, GLONASS, BeiDou, Galileo, QZSS |
| COMMUNICATIONS | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| Data Transmission | GPRS, EDGE, EV-DO, HSDPA, HSUPA, HSPA+, VoLTE, FDD-LTE, TDD-LTE | GPRS, FDD-LTE, TDD-LTE, Gigabit LTE, LAA, 5G NR FR1 | |
|---|---|---|---|
| 2G Band | - | 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 12, Band 20, Band 28, Band 38, Band 39, Band 40 | 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 700a, FDD 800 DD, FDD 700 APT, TDD 2600, TDD 1900, TDD 2300 | 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 | Yes | Both phones have an NFC reader for mobile payments. |
| WLAN Security | WPA3 | - | |
| Messaging Services | SMS, MMS | - |
| MEDIA | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| Supported Digital Audio Standards | WAV, AAC, AMR, MP3, FLAC, apt-X, LDAC, apt-X HD | WAV, AAC, AMR, MP3, FLAC, OGG, MIDI, M4A, apt-X, IMY, RTX, OTA, MID, TWS, RTTL | |
|---|---|---|---|
| Supported Digital Video Standards | MKV, VC-1, XviD, MPEG-4, H.264, M4V, HEVC, VP8, VP9 | MKV, FLV, AVI, MOV, MPEG-4, WMV, ASF, 3GP, H.264, TS, M2TS, WebM, HEVC, 3G2, HEIF, H.265 HEVC, HEIC | |
| Sound Enhancements | Qualcomm TrueWireless Stereo Plus | Qualcomm aptX HD audio, Qualcomm aptX Classic |
| FEATURES | Xiaomi MI 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, digital compass, gyro sensor, ultrasonic proximity sensor, linear rotation vector sensor | Hall sensor, Time of Flight (ToF), dual accelerometers, dual gyroscope, dual magnetometer, dual ambient light sensor, dual proximity sensor | |
| Security Devices | Fingerprint reader (under display) | Fingerprint reader (side) | |
| Additional Phone Features | Infrared remote control, MIMO technology, MU-MIMO technology, MI Turbo, GAME Turbo | MIMO technology, Fast Charging, dual battery, Full Duplex communication, dual microphones with AI-based noise suppression and acoustic echo cancellation |
| OTHERS | Xiaomi MI 9 | Microsoft Surface Duo 2 |
|---|
| Included Accessories | Protective cover, SIM card removal tool, USB-C cable, USB-C audio adapter, 18W QC3.0 charger | SIM card removal tool, USB-C headset, Surface Duo 2 USB-C cable | |
|---|---|---|---|
| Compliant Standards | TUV Rheinland Certified Safe Fast-Charge System | HEARING AID M4/T3 |
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