Xiaomi Poco X3 Pro (J20SI 128GB) vs Samsung Galaxy S21 Ultra (SM-G998U1 512GB)
Side by side comparison between Xiaomi Poco X3 Pro vs Samsung Galaxy S21 Ultra phones, differences, pros, cons and full specifications. What's the better?
,
6.67"
IPS
IPS
1080x2400
48
MP
MP
20mp
6GB
RAM
RAM
Octa-core
5160
mAh
mAh
(Non removable)
vs
6.8"
AMOLED
AMOLED
1440x3200
108
MP
MP
40mp
16GB
RAM
RAM
Octa-core
5000
mAh
mAh
(Non removable)
What's the better phone? Samsung Galaxy S21 Ultra (SM-G998U1 512GB)
The phonemore's choice is much more technical than personal. Therefore, you shouldn't only consider this. Our goal is to help you, but what's important to us may not be important to you. You decide which one is the best! Comment!
6 Advantages 
31 Advantages | 25 Common items in both devices |
| UFS 3.1 |
| 120Hz |
| 16 million |
| PDAF: phase detection autofocus / PDAF: phase detection autofocus on both cameras |
| HDR photo on both cameras / HDR photo/video on both cameras |
| f/1.8 (aperture) |
| Capacitive |
| +18 specs and more in the table below |
Check the comparison table below for more items that are not evaluated in comparison score above.
Highlight differences Clear highlight📱 Model features | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Model | Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) |
| Other model names | POCO X3 Pro M2102J20SI (128GB+6GB RAM) | Galaxy S21 Ultra 5G (SM-G998U1) Unlocked |
| Country or region available |  India |  USA |
| Brand | Xiaomi | Samsung |
| Release date | 3/24/2021, Announced: 3/22/2021 | 1/29/2021, Announced: 1/14/2021 |
| Depth | 9.4 millimeters (0.37 inches) | 8.9 millimeters (0.35 inches) |
| Size (width x height) | 76.8 x 165.3 millimeters (3.02 x 6.51 in) | 75.6 x 165.1 millimeters (2.98 x 6.5 in) |
| Weight | 215 grams (7.53 ounces) | 227 grams (7.95 ounces) |
| Build, materials | Plastic body, glass front | Aluminum frame, glass front/back |
| Protection against water and others | IP53 certified: protection against dust and splashing | IP68 certified: water-resistant up to 1.5 meters for 30min and dust-resistant |
📲 Display | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Display type | TFT IPS LCD | Dynamic AMOLED |
| Screen size | 6.67" inches | 6.8" inches |
| Screen-to-body ratio | ~84.6% (screen-to-body ratio) | ~89.4% (screen-to-body ratio) |
| Display resolution | 1080x2400 pixels (20:9) | 1440x3200 pixels (20:9) |
| Touchscreen | Capacitive Multitouch | Capacitive Multitouch 10-points |
| Pixel density (dot pitch) | 395 PPI | 516 PPI |
| Colors | 16 million | 16 million |
| Scratch-resistant glass | Gorilla Glass 6 | Gorilla Glass Victus |
| Refresh rate | 120Hz | 120Hz |
| Display features | 450nits[typ] HDR10 | 1500nits[peak] HDR10+ Always-On Display |
🤖 Operating System | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| System version | Android 11 | Android 11 |
| Firmware update | Android 13 | Android 15 |
| User Interface | MIUI 12.5 / 13 / 14 | One UI 3.1 / 4.1 / 5.1 / 6.0 / 7.0 |
⚙️ Processor | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Chipset | 64bit: Qualcomm Snapdragon 860 (SM8150-AC) (7nm) | 64bit: Qualcomm Snapdragon 888 (SM8350) (5nm) |
| CPU | Octa-core, 3 processors: 1x 2.96GHz Kryo 485 Gold (Single-core) 3x 2.42GHz Kryo 485 Gold (Triple-core) 4x 1.78GHz Kryo 485 Silver (Quad-core) | Octa-core, 3 processors: 1x 2.84GHz Kryo 680 (Single-core) 3x 2.42GHz Kryo 680 (Triple-core) 4x 1.8GHz Kryo 680 (Quad-core) |
| GPU graphical controller | Qualcomm Adreno 640 (250-672MHz) | Qualcomm Adreno 660 (840MHz) |
| Performance (benchmark) | AnTuTu: 483527 (v8) Geekbench: 2574 (v5.1) GFXBench: 38fps (ES 3.1 onscreen) | AnTuTu: 681099 (v8), 809165 (v9) Geekbench: 3539 (v5.2) GFXBench: 54fps (ES 3.1 onscreen) |
💽 Memory and storage | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| RAM memory | 6GB LPDDR4X | 16GB LPDDR5 |
| Internal storage | 128GB (106GB available) UFS 3.1 | 512GB (457GB available) UFS 3.1 |
| External storage | Until 1TB microSD, microSDXC (hybrid slot/shares the same SIM-2 slot) | Not supported |
📶 Mobile networks | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Dual-SIM | Dual-SIM Standby - Call active on one sim card (hybrid slot/shares the same microSD slot) | Dual-SIM Standby - Call active on one sim card |
| SIM card | 2 slots (Dual-SIM) nano-SIM (4FF) | 1 slot (Single-SIM) nano-SIM (4FF) + e-SIM |
| Maximum Download / Upload | 800/150 Mbps | 5000/1920 Mbps |
| Network technology | 2G, 3G, 4G | 2G, 3G, 4G, 5G |
| Frequency, bands | Expand band details Collapse details | |
| GSM MHz band | Quad-Band 850/900/1800/1900 | Quad-Band 850/900/1800/1900 |
| Primary 2G network | GSM 850/900/1800/1900 | CDMA 800/1900, GSM 850/900/1800/1900 |
| Primary 3G network | UMTS 850/900/1700/1900/2100 | CDMA2000 1xEV-DO UMTS 850/900/1700/1900/2100 |
| Primary 4G network | LTE Cat15/13 (1, 2, 3, 4, 5, 7, 8, 20, 28) TD-LTE (38, 40, 41) | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 66, 71) TD-LTE (38, 39, 40, 41, 46, 48) VoLTE |
| Primary 5G network | Not supported | SA/NSA/Sub6 (2, 5, 25, 41, 66, 71) mmWave (260, 261) |
| Primary data network | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 |
| Secondary 2G network | GSM 850/900/1800/1900 | CDMA 800/1900, GSM 850/900/1800/1900 |
| Secondary 3G network | UMTS 850/900/1700/1900/2100 | CDMA2000 1xEV-DO UMTS 850/900/1700/1900/2100 |
| Secondary 4G network | LTE Cat15/13 (1, 2, 3, 4, 5, 7, 8, 20, 28) TD-LTE (38, 40, 41) | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 66, 71) TD-LTE (38, 39, 40, 41, 46, 48) VoLTE |
| Secondary data network | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 |
📷 Camera | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Back camera (main camera) | (quad camera) 48 megapixels 8MP ultrawide f/2.2119°1.0µm 2MP macro f/2.4 2MP depth f/2.4 | (quad camera) 108 megapixels 10MP periscope telephoto f/4.9240mm1/3.24"1.22µmPDAFOIS10x-optical-zoom 10MP telephoto f/2.470mm1/3.24"1.22µmPDAFOIS3x-optical-zoom 12MP ultrawide f/2.213mm1/2.55"1.4µmPDAFSuper-Steady-video |
| Main camera resolution | 8000x6000 pixels | 12000x9000 pixels |
| Video recording (primary) | 4K UHD (3840x2160) 30 fps | 8K UHD (7680x4320) 24 fps |
| Flash | Dual-LED flash | LED flash |
| Focal aperture | f/1.8 (aperture) | f/1.8 (aperture) |
| Focal length | feature not registered | 26mm (lens) |
| Sensor size | 1/2" inches | 1/1.33" inches |
| Pixel size | 0.8µm pixel | 1.8µm pixel |
| Autofocus | PDAF: phase detection autofocus | PDAF: phase detection autofocus on both cameras |
| Touch focus | Supported | Supported |
| Image stabilization | EIS: Digital stabilization | OIS: Optical stabilization |
| Zoom | Only digital zoom | Digital and optical zoom |
| Face/smile detection | Face detection, Smile detection | Face detection, Smile detection |
| BSI sensor | Not supported | Supported |
| HDR | HDR photo on both cameras | HDR photo/video on both cameras |
| Camera extras | 1080p@960fps | 4K@60fps 1080p@240fps 720p@960fps |
📸 Front camera | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Front camera (secondary) | 20 megapixels | 40 megapixels |
| Front camera resolution | 5184x3840 pixels | 7296x5472 pixels |
| Video recording (secondary) | Full HD (1920x1080) | 4K UHD (3840x2160) |
| Front flash | Not supported | Not supported |
| Focal aperture | f/2.2 (aperture) | f/2.2 (aperture) |
| Focal length | feature not registered | 26mm (lens) |
| Sensor size | 1/3.4" inches | 1/2.8" inches |
| Pixel size | 0.8µm pixel | 0.7µm pixel |
🔉 Sound and multimedia | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Loudspeaker | Stereo sound with dual speakers | Stereo sound 32-bit/384kHz Dolby Atmos Tuned by AKG |
| Active noise cancellation | 2 microphones or more | 3 microphones |
| Radio | FM | FM |
| TV | Not supported | Not supported |
| Video formats | MP4, H.265, H.264, H.263, XviD, MKV | MP4, H.265, H.264, H.263, XviD, MKV |
| Audio formats | MP3, WAV, WMA, eAAC+, FLAC | MP3, WAV, WMA, eAAC+, FLAC |
🔌 Connectivity | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| USB | USB 2.0 Type-C, USB OTG On-The-Go | USB 3.2 Type-C, USB OTG On-The-Go |
| Audio output | 3.5mm jack | Type-C reversible connector |
| TV output | USB Type-C (reversible) | USB Type-C (reversible) |
| Bluetooth | 5.0 + A2DP/LE | 5.2 + A2DP/LE |
| WiFi | 802.11 a/b/g/n/ac [wifi5] (2.4GHz, 5GHz) + MIMO WiFi Direct, hotspot | 802.11 a/b/g/n/ac/ax [wifi6] (2.4GHz, 5GHz) + MIMO WiFi Direct, hotspot |
| DLNA | Not supported | Supported |
| GPS | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou |
| NFC | Not supported | Supported |
| Infrared port | Supported | Not supported |
🧭 Sensors | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Sensors | Accelerometer Ambient light sensor Compass Face unlock Fingerprint sensor (side-mounted) Gyroscope Proximity sensor | Accelerometer Ambient light sensor Barometer Compass Face unlock Fingerprint sensor (under display) Gesture Gyroscope Hall effect Proximity sensor UWB (Ultra Wideband) |
| Vibrating alert | Supported | Supported |
🔋 Battery | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Battery type | LiPo: li-ion polymer (Non removable) | LiPo: li-ion polymer (Non removable) |
| Battery capacity | 5160 mAh | 5000 mAh |
| Charger, watts | 33W Wired fast charging | 25W Wired fast charging USB Power Delivery 3.0 |
| Inductive / wireless charging | Not supported | 15W Qi wireless charging (Qi/PMA) 4.5W Reverse wireless charging |
| Talk time autonomy | feature not registered | feature not registered |
| Standby | feature not registered | feature not registered |
➕ Other features | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| Call control | Voice dialing, Voice recorder, Voice commands | Voice dialing, Voice recorder, Voice commands |
| Messaging | SMS (T9), MMS, E-mail, Push mail | SMS (T9), MMS, E-mail, Push mail |
| Hands-free calling | Supported | Supported |
| Video calling | Supported | Supported |
| Ringtones | Polyphonic and customized | Polyphonic and customized |
| Web browser | HTML, XHTML, HTML5 | HTML, XHTML, HTML5 |
| Antenna | Internal antenna | Internal antenna |
| Qwerty physical keyboard | Not supported | Not supported |
| Miscellaneous | • Colors: Phantom Black, Frost Blue, Metal Bronze • Silicone Case included • Cooling up to 6 °C • LiquidCool 1.0 Plus | • Colors: Phantom Black, Silver, Titanium, Navy, Brown • Samsung Pay (Visa, MasterCard) • Samsung DeX • Stylus pen support |
☢️ Radiation rate | ||
| Xiaomi Poco X3 Pro (J20SI 128GB) | Galaxy S21 Ultra (SM-G998U1 512GB) | |
| SAR 1.6W/kg (USA, Mexico, etc.) | 0.99W/kg (head), 0.67W/kg (body) | 0.77W/kg (head), 1.02W/kg (body) |
| SAR 2W/kg (Europe, UK, etc.) | 0.57W/kg (head), 0.9W/kg (body) | feature not registered |