Samsung Galaxy S21 Ultra (SM-G998U1 512GB) vs Xiaomi 15 (China 256GB/12GB)
Side by side comparison between Samsung Galaxy S21 Ultra vs Xiaomi 15 phones, differences, pros, cons and full specifications. What's the better?
,
6.8"
AMOLED
AMOLED
1440x3200
108
MP
MP
40mp
16GB
RAM
RAM
Octa-core
5000
mAh
mAh
(Non removable)
vs
6.36"
AMOLED
AMOLED
1200x2670
50
MP
MP
32mp
12GB
RAM
RAM
Octa-core
5400
mAh
mAh
(Non removable)
What's the better phone? Xiaomi 15 (China 256GB/12GB)
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!
10 Advantages 
14 Advantages | 37 Common items in both devices |
| Aluminum frame, glass front/back / Aluminum body, glass front |
| Dynamic AMOLED / LTPO AMOLED |
| HDR10+ / Dolby Vision/HDR10+ |
| 120Hz |
| Digital and optical zoom |
| PDAF: phase detection autofocus on both cameras / PDAF: phase detection autofocus |
| OIS: Optical stabilization |
| +30 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 | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Model | Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) |
| Other model names | Galaxy S21 Ultra 5G (SM-G998U1) Unlocked | Xiaomi 15 24129PN74C |
| Country or region available |  USA |  China |
| Brand | Samsung | Xiaomi |
| Release date | 1/29/2021, Announced: 1/14/2021 | 10/29/2024 |
| Depth | 8.9 millimeters (0.35 inches) | 8.4 millimeters (0.33 inches) |
| Size (width x height) | 75.6 x 165.1 millimeters (2.98 x 6.5 in) | 71.2 x 152.3 millimeters (2.8 x 6 in) |
| Weight | 227 grams (7.95 ounces) | 192 grams (6.72 ounces) |
| Build, materials | Aluminum frame, glass front/back | Aluminum body, glass front |
| Protection against water and others | IP68 certified: water-resistant up to 1.5 meters for 30min and dust-resistant | IP68 certified: water-resistant up to 1.5 meters for 30min and dust-resistant |
📲 Display | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Display type | Dynamic AMOLED | LTPO AMOLED |
| Screen size | 6.8" inches | 6.36" inches |
| Screen-to-body ratio | ~89.4% (screen-to-body ratio) | ~90% (screen-to-body ratio) |
| Display resolution | 1440x3200 pixels (20:9) | 1200x2670 pixels (20:9) |
| Touchscreen | Capacitive Multitouch 10-points | Capacitive Multitouch 10-points |
| Pixel density (dot pitch) | 516 PPI | 460 PPI |
| Colors | 16 million | 68 billion |
| Scratch-resistant glass | Gorilla Glass Victus | Dragon Crystal Glass |
| Refresh rate | 120Hz | 120Hz |
| Display features | 1500nits[peak] HDR10+ Always-On Display | 3200nits[peak] Dolby Vision/HDR10+ Touch Sampling Rate: 300Hz |
🤖 Operating System | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| System version | Android 11 | Android 15 |
| Firmware update | Android 15 | feature not registered |
| User Interface | One UI 3.1 / 4.1 / 5.1 / 6.0 / 7.0 | HyperOS 2 |
⚙️ Processor | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Chipset | 64bit: Qualcomm Snapdragon 888 (SM8350) (5nm) | 64bit: Qualcomm Snapdragon 8 Elite (SM8750-AB) (3nm) |
| CPU | 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) | Octa-core, 2 processors: 2x 4.32GHz Oryon V2 Phoenix L (Dual-core) 6x 3.53GHz Oryon V2 Phoenix M (Hexa-core) |
| GPU graphical controller | Qualcomm Adreno 660 (840MHz) | Qualcomm Adreno 830 (1100MHz) |
| Performance (benchmark) | AnTuTu: 681099 (v8), 809165 (v9) Geekbench: 3539 (v5.2) GFXBench: 54fps (ES 3.1 onscreen) | AnTuTu: 2534643 (v10) Geekbench: 9419 (v6) |
💽 Memory and storage | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| RAM memory | 16GB LPDDR5 | 12GB LPDDR5X |
| Internal storage | 512GB (457GB available) UFS 3.1 | 256GB (220GB available) UFS 4.0 |
| External storage | Not supported | Not supported |
📶 Mobile networks | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Dual-SIM | Dual-SIM Standby - Call active on one sim card | Dual-SIM Standby - Call active on one sim card |
| SIM card | 1 slot (Single-SIM) nano-SIM (4FF) + e-SIM | 2 slots (Dual-SIM) nano-SIM (4FF) + e-SIM |
| Maximum Download / Upload | 5000/1920 Mbps | 3000/1024 Mbps |
| Network technology | 2G, 3G, 4G, 5G | 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 | CDMA 800/1900, GSM 850/900/1800/1900 | GSM 850/900/1800/1900 |
| Primary 3G network | CDMA2000 1xEV-DO UMTS 850/900/1700/1900/2100 | UMTS 850/900/1700/1900/2100 |
| Primary 4G network | 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 | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 17, 18, 19, 20, 26, 28, 66) TD-LTE (34, 38, 39, 40, 41, 42, 48) VoLTE |
| Primary 5G network | SA/NSA/Sub6 (2, 5, 25, 41, 66, 71) mmWave (260, 261) | SA/NSA/Sub6 (1, 2, 3, 5, 12, 20, 26, 28, 38, 40, 41, 48, 66, 77, 78, 80, 81, 83, 84, 89) |
| Primary data network | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 |
| Secondary 2G network | CDMA 800/1900, GSM 850/900/1800/1900 | GSM 850/900/1800/1900 |
| Secondary 3G network | CDMA2000 1xEV-DO UMTS 850/900/1700/1900/2100 | UMTS 850/900/1700/1900/2100 |
| Secondary 4G network | 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 | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 17, 18, 19, 20, 26, 28, 66) TD-LTE (34, 38, 39, 40, 41, 42, 48) VoLTE |
| Secondary data network | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 |
📷 Camera | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Back camera (main camera) | (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 | (triple camera) 50 megapixels 50MP telephoto f/2.060mm1/2.76"0.64µmPDAFOIS2.6x-optical-zoom 50MP ultrawide f/2.214mm115°1/2.76"0.64µm |
| Main camera resolution | 12000x9000 pixels | 8160x6120 pixels |
| Video recording (primary) | 8K UHD (7680x4320) 24 fps | 8K UHD (7680x4320) 30 fps |
| Flash | LED flash | Dual-LED flash |
| Focal aperture | f/1.8 (aperture) | f/1.6 (aperture) |
| Focal length | 26mm (lens) | 23mm (lens) |
| Sensor size | 1/1.33" inches | 1/1.31" inches |
| Pixel size | 1.8µm pixel | 1.2µm pixel |
| Autofocus | PDAF: phase detection autofocus on both cameras | PDAF: phase detection autofocus |
| Touch focus | Supported | Supported |
| Image stabilization | OIS: Optical stabilization | OIS: Optical stabilization |
| Zoom | Digital and optical zoom | Digital and optical zoom |
| Face/smile detection | Face detection, Smile detection | Face detection, Smile detection |
| BSI sensor | Supported | Supported |
| HDR | HDR photo/video on both cameras | HDR photo/video on both cameras |
| Camera extras | 4K@60fps 1080p@240fps 720p@960fps | 8K@24/30fps (HDR) 4K@24/30/60fps (HDR10+, 10-bit Dolby Vision HDR, 10-bit LOG) 1080p@30/60/120/240/960fps 720p@1920fps Leica Summilux |
📸 Front camera | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Front camera (secondary) | 40 megapixels | 32 megapixels |
| Front camera resolution | 7296x5472 pixels | 6528x4896 pixels |
| Video recording (secondary) | 4K UHD (3840x2160) | 4K UHD (3840x2160) |
| Front flash | Not supported | Not supported |
| Focal aperture | f/2.2 (aperture) | f/2.0 (aperture) |
| Focal length | 26mm (lens) | 21mm (lens) |
| Sensor size | 1/2.8" inches | 1/3.14" inches |
| Pixel size | 0.7µm pixel | 0.7µm pixel |
🔉 Sound and multimedia | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Loudspeaker | Stereo sound 32-bit/384kHz Dolby Atmos Tuned by AKG | Stereo sound 24-bit/192kHz Dolby Atmos Hi-Res |
| Active noise cancellation | 3 microphones | 4 microphones |
| Radio | FM | Not supported |
| 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 | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| USB | USB 3.2 Type-C, USB OTG On-The-Go | USB 3.2 Type-C, USB OTG On-The-Go |
| Audio output | Type-C reversible connector | Type-C reversible connector |
| TV output | USB Type-C (reversible) | USB Type-C (reversible) |
| Bluetooth | 5.2 + A2DP/LE | 6.0 + A2DP/LE |
| WiFi | 802.11 a/b/g/n/ac/ax [wifi6] (2.4GHz, 5GHz) + MIMO WiFi Direct, hotspot | 802.11 a/b/g/n/ac/ax/be [wifi7/6E/6] (2.4GHz, 5GHz, 6GHz) + MIMO WiFi Direct, hotspot |
| DLNA | Supported | Not supported |
| GPS | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou, QZSS |
| NFC | Supported | Supported |
| Infrared port | Not supported | Supported |
🧭 Sensors | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Sensors | Accelerometer Ambient light sensor Barometer Compass Face unlock Fingerprint sensor (under display) Gesture Gyroscope Hall effect Proximity sensor UWB (Ultra Wideband) | Accelerometer Ambient light sensor Barometer Compass Face unlock Fingerprint sensor (under display) Gyroscope Proximity sensor |
| Vibrating alert | Supported | Supported |
🔋 Battery | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| Battery type | LiPo: li-ion polymer (Non removable) | Li-Si: lithium-silicon (Non removable) |
| Battery capacity | 5000 mAh | 5400 mAh |
| Charger, watts | 25W Wired fast charging USB Power Delivery 3.0 | 90W Wired fast charging Reverse charging by cable Quick Charge 3+ USB Power Delivery 3.0 |
| Inductive / wireless charging | 15W Qi wireless charging (Qi/PMA) 4.5W Reverse wireless charging | 50W Qi Wireless charging (Qi/WPC) 10W Reverse wireless charging |
| Talk time autonomy | feature not registered | feature not registered |
| Standby | feature not registered | feature not registered |
➕ Other features | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| 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, Silver, Titanium, Navy, Brown • Samsung Pay (Visa, MasterCard) • Samsung DeX • Stylus pen support | • Colors: Black, White, Green, Lilac, Liquid Silver • Xiaomi HyperAI |
☢️ Radiation rate | ||
| Galaxy S21 Ultra (SM-G998U1 512GB) | Xiaomi 15 (China 256GB/12GB) | |
| SAR 1.6W/kg (USA, Mexico, etc.) | 0.77W/kg (head), 1.02W/kg (body) | feature not registered |
| SAR 2W/kg (Europe, UK, etc.) | feature not registered | 0.99W/kg (head), 1W/kg (body) |