In depth comparison and review of Xiaomi Redmi Note 9 and Samsung Galaxy S21 Ultra 5G. 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 | Samsung Galaxy S21 Ultra 5G |
|---|
| Product Type | Smartphone | Smartphone | |
|---|---|---|---|
| Manufacturer Model Number | - | SM-G998B/DS | |
| Form Factor | Touch | Touch | |
| Height | 162.3 mm | 161.5 mm | Xiaomi Redmi Note 9 has greater height than Samsung Galaxy S21 Ultra 5G. |
| Width | 77.2 mm | 75.6 mm | Xiaomi Redmi Note 9 has greater width than Samsung Galaxy S21 Ultra 5G. |
| Depth | 8.9 mm | 8.9 mm | Both phones are the same depth. |
| Weight | 199 g | 227 g | Xiaomi Redmi Note 9 is lighter than Xiaomi Redmi Note 9. |
| Body Colour | Forest green | Phantom silver | Phantom black | Phantom navy | Phantom brown | Phantom titanium | |
| Protection | Splashproof | Dustproof, splashproof, water-resistant | |
| Waterproof (Water-resistant) | - | Yes | Samsung Galaxy S21 Ultra 5G is waterproof. |
| IP rating | - | IP68 | |
| SAR Value | 2.262 W/kg (limb), 1.138 W/kg (body), 0.795 W/kg (head) | 1.58 W/kg (body), 0.714 W/kg (head), 2.56 W/kg (limb) | |
| 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 | Samsung Galaxy S21 Ultra 5G |
|---|
| Display Type | - | OLED display | |
|---|---|---|---|
| Display Technology | - | Infinity-O Dynamic AMOLED 2X | |
| Screen Size (Display Size) | 6.53" | 6.8" | Samsung Galaxy S21 Ultra 5G has larger screen size than Xiaomi Redmi Note 9. |
| Screen Resolution (Display Resolution) | 2340 x 1080 pixels | 3200 x 1440 pixels | Samsung Galaxy S21 Ultra 5G has better screen resolution than Xiaomi Redmi Note 9. |
| Display Format | Full HD+ | QHD+ | |
| Pixel Density | - | 515 ppi | |
| Aspect Ratio | 19.5:9 | - | |
| Max Brightness | 450 cd/m² | - | |
| Colour Depth | - | 16.7 million colours | |
| Contrast Ratio | 1500:1 | - | |
| HDR | - | Yes | Samsung Galaxy S21 Ultra 5G has HDR. |
| HDR Technology | - | HDR10+ | |
| Display Enhancement Technology | - | Eye Comfort Shield | |
| Display Refresh Rate | - | 120 Hz | |
| Display Features | Reading mode 2.0, Dot Display, Full Screen gestures | Edge Screen, AOD(Always On Display) | |
| Display Protection (Screen Protector) | Corning Gorilla Glass 5 (scratch resistant glass) | Corning Gorilla Glass Victus (scratch resistant glass) |
| PROCESSOR | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| Processor Type (CPU) | MediaTek Helio G85 | Samsung Exynos 2100 | |
|---|---|---|---|
| Clock Speed | 2 GHz | 2.9 GHz | Samsung Galaxy S21 Ultra 5G has higher clock speed than Xiaomi Redmi Note 9. |
| Processor Core Qty | 8-core | 8-core | Both phones have the same number of phone cores. |
| Graphics System (GPU) | ARM G52 MC2 | Mali-G78 MP14 |
| MEMORY | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| RAM | 3 GB | LPDDR5 SDRAM - 12 GB | Samsung Galaxy S21 Ultra 5G has more RAM than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Internal Memory Size (Storage Capacity) | 64 GB | 128 GB | Samsung Galaxy S21 Ultra 5G has more internal memory than Xiaomi Redmi Note 9. |
| User Memory | - | 101.7 GB | |
| Supported Flash Memory Cards (Expandable Memory) | microSD | - |
| CAMERA | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| MAIN CAMERA |
|---|
| Number of Main Cameras | 4 | 4 | |
|---|---|---|---|
| Sensor Resolution | 48 Megapixel | 12 Megapixel | Xiaomi Redmi Note 9 has better camera resolution than Samsung Galaxy S21 Ultra 5G. |
| Sensor Size | 1/2" | - | |
| Lens Type | - | Ultra wide-angle lens | |
| Lens Aperture | F/1.79 | F/2.2 | Xiaomi Redmi Note 9 has better lens aperture than Xiaomi Redmi Note 9. |
| Lens Construction | 6-element | - | |
| Field of View (FoV) | 79.4 degree(s) | 120 degree(s) | Samsung Galaxy S21 Ultra 5G has larger lens field of view than Xiaomi Redmi Note 9. |
| Pixel Size | 0.8 μm | 1.4 μm | Samsung Galaxy S21 Ultra 5G has larger camera pixel size than Xiaomi Redmi Note 9. |
| Optical Image Stabiliser (OIS) | - | Optical Image Stabiliser (OIS) | Samsung Galaxy S21 Ultra 5G has optical stabilisation. |
| Focus Adjustment | Automatic | Automatic | |
| Laser Auto Focus | - | Yes | |
| Optical Zoom | - | 3x | |
| Digital Zoom | - | 100x | |
| Self-Timer Delay | - | Yes | |
| Special Effects | HDR, Kaleidoscope | Face retouch, Grid Line | |
| HDR Mode | - | Auto HDR mode | |
| Camera Modes | Burst mode, Panorama, night mode, Smart ultra-wide angle mode, Photo timer, Custom watermark, Documents, Beautify, Levelling, Cinematic portraits | Panorama, Slow motion mode, Pro mode, HYPERLAPSE, Super Slow-mo, Flowers, Greenery, Trees, Sky, Beaches, Watersides, Snow, Backlit, Text, Food, Face, Baby, Person, Dog, Cat, People, Sunset, Sunrise, City, Waterfall, Scenery, Stage, Vehicles, Drinks, Animal, Shoes, Indoor, Clothes, Night view, Night, Motion Photo, Mountain, Single Take, Pro Video, Director's View | |
| Face Recognition (Face ID) | Face recognition | - | Xiaomi Redmi Note 9 has face detection. |
| Light Source | Flash | High CRI 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 60 fps, 1280 x 720 (720p) at 30 fps, 3840 x 2160 (4K) at 60 fps, Super slow motion video 1280 x 720 (720p) at 960 fps, Slo-mo video 1920 x 1080 (1080p) at 240 fps, 7680 x 4320 (UHD 8K) at 24fps, Hyperlapse 4K video support at 30 fps, Super Steady 1080p video support 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 | Playback zoom, blink detection, VDIS (Video Digital Image Stabilisation), Tracking AF, Video location tags, Scene Optimiser, Flaw detection, Shot suggestions, blur detection, HDR10+ recording, Super steady, Quick Measure, Zoom-In Mic, Space Zoom, Take 33MP still photos while playing 8K video, Hybrid Optic Zoom 3x, Super Resolution Zoom up to 30x, Digital zoom up to 12x for video |
| SECOND CAMERA |
|---|
| Sensor Resolution (2nd Camera) | 8 Megapixel | 108 Megapixel | Samsung Galaxy S21 Ultra 5G has better second camera resolution than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Sensor Size (2nd Camera) | 1/4" | 1/1.33" | Xiaomi Redmi Note 9 has better second camera sensor size than Samsung Galaxy S21 Ultra 5G. |
| Lens Type (2nd Camera) | Ultra wide-angle lens | Wide-angle lens | |
| Lens Aperture (2nd Camera) | F/2.2 | F/1.8 | Samsung Galaxy S21 Ultra 5G 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) | 83 degree(s) | Xiaomi Redmi Note 9 has larger second camera lens field of view than Samsung Galaxy S21 Ultra 5G. |
| Pixel Size (2nd Camera) | 1.2 μm | 0.8 μm | Xiaomi Redmi Note 9 has larger second camera pixel size than Samsung Galaxy S21 Ultra 5G. |
| Camera Features (2nd Camera) | 5-piece lens | Phase Detect Auto-Focus (PDAF), OIS (Optical Image Stabilisation) |
| THIRD CAMERA |
|---|
| Sensor Resolution (3rd Camera) | 2 Megapixel | 10 Megapixel | Samsung Galaxy S21 Ultra 5G has higher resolution third camera than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Lens Type (3rd Camera) | - | Telephoto lens | |
| Lens Aperture (3rd Camera) | F/2.4 | F/2.4 | Both phones have the same lens aperture of the third camera. |
| Field of View (3rd Camera) | - | 35 degree(s) | |
| Pixel Size (3rd Camera) | 1.75 μm | 1.22 μm | Xiaomi Redmi Note 9 has larger third camera pixel size than Samsung Galaxy S21 Ultra 5G. |
| Camera Functions (3rd Camera) | Macro camera | - | |
| Camera Features (3rd Camera) | AF (2cm-10cm) | Dual Pixel AF |
| FOURTH CAMERA |
|---|
| Sensor Resolution (4th Camera) | 2 Megapixel | 10 Megapixel | Samsung Galaxy S21 Ultra 5G has higher resolution fourth camera than Xiaomi Redmi Note 9. |
|---|---|---|---|
| Sensor Size (4th Camera) | 1/5" | - | |
| Lens Type (4th Camera) | - | Telephoto lens | |
| Lens Aperture (4th Camera) | F/2.4 | F/4.9 | Xiaomi Redmi Note 9 has better fourth camera lens aperture than Xiaomi Redmi Note 9. |
| Lens Element Qty (4th Camera) | 3-element | - | |
| Field of View (4th Camera) | - | 10 degree(s) | |
| Pixel Size (4th Camera) | 1.75 μm | 1.22 μm | Xiaomi Redmi Note 9 has larger fourth camera pixel size than Samsung Galaxy S21 Ultra 5G. |
| Camera Functions (4th Camera) | Depth camera | - | |
| Camera Features (4th Camera) | - | Dual Pixel AF |
| FRONT CAMERA |
|---|
| Number of Front Cameras | 1 | 1 | |
|---|---|---|---|
| Sensor Resolution (Front) | 13 Megapixel | 40 Megapixels | Samsung Galaxy S21 Ultra 5G has better front camera resolution than Xiaomi Redmi Note 9. |
| Sensor Size (Front) | 1/3.06" | - | |
| Lens Aperture (Front) | F/2.25 | F/2.2 | Samsung Galaxy S21 Ultra 5G has better front lens aperture than Xiaomi Redmi Note 9. |
| Lens Element Qty (Front) | 5-element | - | |
| Field of View (Front) | 74 degree(s) | 80 degree(s) | Samsung Galaxy S21 Ultra 5G has larger front lens field of view than Xiaomi Redmi Note 9. |
| Pixel Size (Front) | 1.12 μm | 0.7 μm | Xiaomi Redmi Note 9 has larger front camera pixel size than Samsung Galaxy S21 Ultra 5G. |
| Focus Adjustment | - | Automatic | |
| 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 | Phase Detect Auto-Focus (PDAF) |
| BATTERY AND CHARGING | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| Battery Capacity (Battery Size) | 5020 mAh | 5000 mAh | Xiaomi Redmi Note 9 has larger battery capacity than Samsung Galaxy S21 Ultra 5G. |
|---|---|---|---|
| Fast Charging Technology | - | Qualcomm Quick Charge 2.0, Adaptive Fast Charging, Samsung Super Fast Charging, Power Delivery 3.0 | Samsung Galaxy S21 Ultra 5G has fast charging technology. |
| Wireless Charging | - | Yes | Samsung Galaxy S21 Ultra 5G can be charged wirelessly. |
| Wireless Charging Standards | - | WPC, Qi, Fast Wireless Charging 2.0, Wireless PowerShare | |
| Talk Time | 1980 minutes | 2460 minutes | Samsung Galaxy S21 Ultra 5G has longer battery life when making calls than Xiaomi Redmi Note 9. |
| 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 (4G): up to 2460 min Active online usage (LTE): up to 18 hrs Active online usage (Wi-Fi): up to 18 hrs Playback (wireless video): up to 22 hrs Playback (wireless audio): up to 81 hrs |
|
| Battery Technology | Lithium polymer | - |
| CELLULAR | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| Technology | WCDMA (UMTS) / GSM | WCDMA (UMTS) / GSM | |
|---|---|---|---|
| Mobile Broadband Generation | 4G | 5G | Samsung Galaxy S21 Ultra 5G has more advanced generation mobile network. |
| Operating System | - | Android 11 | |
| Intelligent Assistant | - | Bixby | |
| Payment Technology | - | Samsung Pay | |
| Navigation | GPS, A-GPS, GLONASS, BeiDou, Galileo | GPS, GLONASS, BeiDou, Galileo |
| COMMUNICATIONS | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| Data Transmission | VoLTE, FDD-LTE, TDD-LTE | FDD-LTE, TDD-LTE, 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 4, Band 5, Band 8 | |
| 3G UMTS Frequency | 2100, 1900, 1700, 850, 900 | 2100, 1900, 1700, 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 17, Band 18, Band 19, Band 20, Band 25, Band 26, Band 28, Band 32, Band 38, Band 39, Band 40, Band 41, Band 66 | |
| 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 700b, FDD 800 lower, FDD 800 upper, FDD 800 DD, FDD 1900+, FDD 850+, FDD 700 APT, FDD 1500 L, TDD 2600, TDD 1900, TDD 2300, TDD 2500, FDD 1700 - 2110 AWS-3 | |
| 5G NR Band | - | N1, n3, n5, n7, n8, n20, n28, n38, n41, n66, n77, n78, n40 | |
| 5G NR Frequency | - | FDD 2100, FDD 1800, FDD 850, FDD 2600, FDD 900, FDD 800, FDD 700APT, TDD TD 2600, TDD TD 2500, FDD AWS-3, TDD TD 3700, TDD TD 3500, TDD 2300 | |
| Wireless Interface | IEEE 802.11a/b/g/n/ac | IEEE 802.11a/b/g/n/ac/ax | |
| Bluetooth | Bluetooth 5.0 | Bluetooth 5.2 | |
| NFC | - | Yes | Samsung Galaxy S21 Ultra 5G has NFC reader for mobile payments. |
| MEDIA | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| Supported Digital Audio Standards | WAV, AAC, AMR, MP3, FLAC, APE (Monkey's Audio) | WAV, WMA, AAC, PCM, AMR, MP3, FLAC, XMF, OGG, MIDI, APE (Monkey's Audio), M4A, DSF, DSD, MXMF, OGA, 3GA, AWB, IMY, RTTTL, RTX, OTA, DFF, MID, DSD64, DSD128 | |
|---|---|---|---|
| Supported Digital Video Standards | MKV, XviD, M4V, MP4 | MKV, FLV, AVI, WMV, ASF, 3GP, M4V, WebM, 3G2, MP4 | |
| Sound Enhancements | - | Dolby Digital Plus sound, Dolby Atmos sound technology, Surround sound, stereo speakers tuned by AKG, Dolby Digital sound | |
| Audio Amplifier | Smart PA | - |
| FEATURES | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| 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 | Accelerometer, ambient light sensor, proximity sensor, barometer, gyro sensor, hall sensor, geomagnetic sensor | |
| Security Devices | Face recognition, fingerprint reader | Fingerprint reader (under display), face recognition | |
| Additional Phone Features | Infrared remote control, HyperEngine technology | Air View, MIMO technology, Smart Select, Samsung KNOX, Smart View, Live message, Screen off memo, Bixby Vision, Dual Audio, Bixby Routines, Intelligent Performance Enhancer, AR Doodle, PENUP, Bixby key, Samsung Knox Vault, Private Share function, Enhanced Game Booster, Air Command |
| OTHERS | Xiaomi Redmi Note 9 | Samsung Galaxy S21 Ultra 5G |
|---|
| Included Accessories | Protective cover, power adapter, SIM card removal tool, USB-C cable | SIM card removal tool, USB-C to USB-C cable | |
|---|---|---|---|
| Compliant Standards | TUV Rheinland Low Blue Light Certification | IP68, HAC (Hearing Aid Compatible) | |
| Max Depth of Water Resistance | - | 1.5 m |
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