Samsung Galaxy Watch (42mm SM-R815U) vs Xiaomi Amazfit T-Rex
Side by side comparison between Samsung Galaxy Watch vs Xiaomi Amazfit T-Rex smartwatches, differences, pros, cons and full specifications. What's the better?
,
1.2"
AMOLED
AMOLED
360x360
N/A
1.5GB
RAM
RAM
Dual-core
270
mAh
mAh
(Non removable)
vs
1.3"
AMOLED
AMOLED
360x360
N/A
512MB
RAM
RAM
Single-core
390
mAh
mAh
(Non removable)
What's the better smartwatch? Samsung Galaxy Watch (42mm SM-R815U)
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!
13 Advantages 
6 Advantages | 15 Common items in both devices |
| eMMC / eMCP |
| 16 million |
| 360x360 pixels |
| Capacitive |
| Multitouch |
| Accelerometer |
| Ambient light sensor |
| +8 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 Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Model | Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex |
| Other model names | Galaxy Watch 42mm (4G LTE) SM-R815UZDAXAR, Samsung Galileo | Mi Amazfit TRex |
| Country or region available |  USA |  (Global, International) |
| Brand | Samsung | Xiaomi |
| Release date | 8/1/2018 | 1/9/2020, Announced: 1/1/2020 |
| Depth | 12.7 millimeters (0.5 inches) | 13.5 millimeters (0.53 inches) |
| Size (width x height) | 41.9 x 45.7 millimeters (1.65 x 1.8 in) | 47.47 x 47.47 millimeters (1.87 x 1.87 in) |
| Weight | 49 grams (1.72 ounces) | 58 grams (2.03 ounces) |
| Build, materials | Stainless steel body, glass front | Plastic body, glass front |
| Protection against water and others | 5 ATM: 50 meters waterproof. MIL-STD-810G military certified: salt, dust, humidity, rain, vibration, solar radiation, transport and thermal shock resistant. | 5 ATM: 50 meters waterproof |
📲 Display | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Display type | Super AMOLED | AMOLED |
| Screen size | 1.2" inches | 1.3" inches |
| Screen-to-body ratio | ~24.3% (screen-to-body ratio) | ~24.2% (screen-to-body ratio) |
| Display resolution | 360x360 pixels (1:1) | 360x360 pixels |
| Touchscreen | Capacitive Multitouch | Capacitive Multitouch |
| Pixel density (dot pitch) | 424 PPI | 392 PPI |
| Colors | 16 million | 16 million |
| Scratch-resistant glass | Gorilla Glass DX+ | Gorilla Glass 3 |
| Refresh rate | feature not registered | 60Hz |
| Display features | Not supported | Not supported |
🤖 Operating System | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| System version | Tizen 4.0 | Proprietary OS |
| Firmware update | feature not registered | feature not registered |
| User Interface | feature not registered | RTOS |
⚙️ Processor | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Chipset | 64bit: Samsung Exynos 9 Dual 9110 (10nm) | 32bit |
| CPU | Dual-core, 1 processor: 2x 1.15GHz ARM Cortex-A53 (Dual-core) | Single-core, 1 processor: Single-core |
| GPU graphical controller | ARM Mali-T720 MP1 | feature not registered |
| Performance (benchmark) | feature not registered | feature not registered |
💽 Memory and storage | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| RAM memory | 1.5GB LPDDR3 | 512MB LPDDR3 |
| Internal storage | 4GB (1.5GB available) eMMC | 4GB (2GB available) eMCP |
| External storage | Not supported | Not supported |
📶 Mobile networks | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Dual-SIM | Not supported | Not supported |
| SIM card | 1 slot (Single-SIM) e-SIM (Eletronic) | Not supported |
| Maximum Download / Upload | 10 Mbps | feature not registered |
| Network technology | 3G, 4G | feature not registered |
| Frequency, bands | Expand band details Collapse details | |
| GSM MHz band | Not supported | Not supported |
| Primary 2G network | Not supported | Not supported |
| Primary 3G network | UMTS 850/1700/1900 | Not supported |
| Primary 4G network | LTE (Bands 2,4,5,12,13,25,26,66) | Not supported |
| Primary 5G network | Not supported | Not supported |
| Primary data network | UMTS, HSDPA, HSUPA, HSPA+, LTE | Not supported |
| Secondary 2G network | Not supported | Not supported |
| Secondary 3G network | Not supported | Not supported |
| Secondary 4G network | Not supported | Not supported |
| Secondary data network | Not supported | Not supported |
📷 Camera | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Back camera (main camera) | Not supported | Not supported |
| Main camera resolution | Not supported | Not supported |
| Video recording (primary) | Not supported | Not supported |
| Flash | Not supported | Not supported |
| Focal aperture | feature not registered | feature not registered |
| Focal length | feature not registered | feature not registered |
| Sensor size | feature not registered | feature not registered |
| Pixel size | feature not registered | feature not registered |
| Autofocus | Not supported | Not supported |
| Touch focus | Not supported | Not supported |
| Image stabilization | Not supported | Not supported |
| Zoom | Not supported | Not supported |
| Face/smile detection | Not supported | Not supported |
| BSI sensor | Not supported | Not supported |
| HDR | Not supported | Not supported |
| Camera extras | feature not registered | feature not registered |
📸 Front camera | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Front camera (secondary) | Not supported | Not supported |
| Front camera resolution | Not supported | Not supported |
| Video recording (secondary) | Not supported | Not supported |
| Front flash | Not supported | Not supported |
| Focal aperture | feature not registered | feature not registered |
| Focal length | feature not registered | feature not registered |
| Sensor size | feature not registered | feature not registered |
| Pixel size | feature not registered | feature not registered |
🔉 Sound and multimedia | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Loudspeaker | Supported | feature not registered |
| Active noise cancellation | Not supported | Not supported |
| Radio | Not supported | Not supported |
| TV | Not supported | Not supported |
| Video formats | MP4 | feature not registered |
| Audio formats | MP3, WAV, WMA, OGG, eAAC+ | feature not registered |
🔌 Connectivity | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| USB | Not supported | Not supported |
| Audio output | Not supported | Not supported |
| TV output | Not supported | Not supported |
| Bluetooth | 4.2 + A2DP | 5.0 + A2DP/LE |
| WiFi | 802.11 b/g/n [wifi4] (2.4GHz) | Not supported |
| DLNA | Not supported | Not supported |
| GPS | A-GPS, GeoTagging, GLONASS | A-GPS, GeoTagging, GLONASS |
| NFC | Supported | Not supported |
| Infrared port | Not supported | Not supported |
🧭 Sensors | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Sensors | Accelerometer Ambient light sensor Barometer Gyroscope Heart rate Pedometer | Accelerometer Ambient light sensor Compass Heart rate Pedometer SpO2 |
| Vibrating alert | Supported | Supported |
🔋 Battery | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Battery type | Li-Ion: lithium-ion (Non removable) | LiPo: li-ion polymer (Non removable) |
| Battery capacity | 270 mAh | 390 mAh |
| Charger, watts | 3.5W (5V/0.7A) Wired charging | Wired charging |
| Inductive / wireless charging | Qi wireless charging | Magnetic charging (dock) |
| Talk time autonomy | feature not registered | 20 hours |
| Standby | 72 hours (3 days) | 480 hours (20 days) |
➕ Other features | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| Call control | Voice dialing, Voice recorder, Voice commands | Not supported |
| Messaging | SMS (T9), MMS, E-mail, Push mail | SMS (T9), E-mail |
| Hands-free calling | Supported | Not supported |
| Video calling | Not supported | Not supported |
| Ringtones | Polyphonic and customized | feature not registered |
| Web browser | Not supported | Not supported |
| Antenna | Internal antenna | feature not registered |
| Qwerty physical keyboard | Not supported | Not supported |
| Miscellaneous | • Colors: Midnight Black, Rose Gold • Straps: Black, Grey, Red, Yellow, Purple, Pink, Brown • Compatible with standard 20mm straps • Always-on display • Rotating bezel • Samsung Pay • Compatible with Sprint, T-Mobile and Verizon carriers | • Colors: Black, Gray, Camouflage, Army green, Khaki • Watch band: 22mm • BioTracker PPG • 14 sports mode • AppZepp app • Compatible with Android 5.0/iOS 10 and above |
☢️ Radiation rate | ||
| Galaxy Watch (42mm SM-R815U) | Amazfit T-Rex | |
| SAR 1.6W/kg (USA, Mexico, etc.) | 0.961W/kg (head), 1.786W/kg (body) | feature not registered |
| SAR 2W/kg (Europe, UK, etc.) | feature not registered | feature not registered |