Samsung Galaxy S8 Plus (SM-G955U) vs Samsung Galaxy S21 Ultra (SM-G998N 512GB)
Side by side comparison between Samsung Galaxy S8 Plus vs Samsung Galaxy S21 Ultra phones, differences, pros, cons and full specifications. What's the better?
,
6.2"
AMOLED
AMOLED
1440x2960
12.2
MP
MP
8mp
4GB
RAM
RAM
Octa-core
3500
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-G998N 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!
10 Advantages 
23 Advantages | 31 Common items in both devices |
| Aluminum frame, glass front/back |
| Super AMOLED / Dynamic AMOLED |
| 16 million |
| LED flash |
| PDAF on back camera and autofocus front camera / PDAF: phase detection autofocus on both cameras |
| OIS: Optical stabilization |
| BSI sensor |
| +24 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 S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Model | Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) |
| Other model names | Galaxy S8+ G955U Unlocked (Snapdragon), Samsung Dream 2 | 갤럭시 S21 Ultra 5G (SM-G998N Single-SIM) |
| Country or region available |  USA |  South Korea |
| Brand | Samsung | Samsung |
| Release date | 4/21/2017, Announced: 3/29/2017 | 1/29/2021, Announced: 1/14/2021 |
| Depth | 8.1 millimeters (0.32 inches) | 8.9 millimeters (0.35 inches) |
| Size (width x height) | 73.4 x 160 millimeters (2.89 x 6.3 in) | 75.6 x 165.1 millimeters (2.98 x 6.5 in) |
| Weight | 173 grams (6.06 ounces) | 227 grams (7.95 ounces) |
| Build, materials | Aluminum frame, glass front/back | Aluminum frame, glass front/back |
| 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 S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Display type | Super AMOLED | Dynamic AMOLED |
| Screen size | 6.2" inches | 6.8" inches |
| Screen-to-body ratio | ~83.1% (screen-to-body ratio) | ~89.4% (screen-to-body ratio) |
| Display resolution | 1440x2960 pixels (18.5:9) | 1440x3200 pixels (20:9) |
| Touchscreen | Capacitive Multitouch 10-points | Capacitive Multitouch 10-points |
| Pixel density (dot pitch) | 531 PPI | 516 PPI |
| Colors | 16 million | 16 million |
| Scratch-resistant glass | Gorilla Glass 5 | Gorilla Glass Victus |
| Refresh rate | 60Hz | 120Hz |
| Display features | HDR10 | 1500nits[peak] HDR10+ Always-On Display |
🤖 Operating System | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| System version | Android 7.0 Nougat | Android 11 |
| Firmware update | Android 9.0 Pie | Android 14 |
| User Interface | feature not registered | One UI 3.1 / 4.1 / 5.1 / 6.0 |
⚙️ Processor | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Chipset | 64bit: Qualcomm Snapdragon 835 (MSM8998) (10nm) | 64bit: Samsung Exynos 2100 (5nm) |
| CPU | Octa-core, 2 processors: 4x 2.35GHz Kryo 280 (Quad-core) 4x 1.9GHz Kryo 280 (Quad-core) | Octa-core, 3 processors: 1x 2.9GHz ARM Cortex-X1 (Single-core) 3x 2.8GHz ARM Cortex-A78 (Triple-core) 4x 2.2GHz ARM Cortex-A55 (Quad-core) |
| GPU graphical controller | Qualcomm Adreno 540 (670-710MHz) | ARM Mali-G78 MP14 (854MHz) |
| Performance (benchmark) | feature not registered | AnTuTu: 657150 (v8), 727634 (v9) Geekbench: 3457 (v5.2) GFXBench: 51fps (ES 3.1 onscreen) |
💽 Memory and storage | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| RAM memory | 4GB LPDDR4 | 16GB LPDDR5 |
| Internal storage | 64GB (51GB available) UFS 2.0 | 512GB (457GB available) UFS 3.1 |
| External storage | Until 1TB microSD, microSDXC (dedicated slot) | Not supported |
📶 Mobile networks | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Dual-SIM | Not supported | Not supported |
| SIM card | 1 slot (Single-SIM) nano-SIM (4FF) | 1 slot (Single-SIM) nano-SIM (4FF) |
| Maximum Download / Upload | 1024/150 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 | 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 Cat16 (1, 2, 3, 4, 5, 7, 8, 12, 20, 28, 29, 30) TD-LTE (38, 39, 40, 41) | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 66) TD-LTE (38, 39, 40, 41) VoLTE |
| Primary 5G network | Not supported | SA/NSA/Sub6 (77, 78) |
| Primary data network | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA |
| 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 S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Back camera (main camera) | 12.2 megapixels | (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 | 4032x3024 pixels | 12000x9000 pixels |
| Video recording (primary) | 4K UHD (3840x2160) 30 fps | 8K UHD (7680x4320) 24 fps |
| Flash | LED flash | LED flash |
| Focal aperture | f/1.7 (aperture) | f/1.8 (aperture) |
| Focal length | 26mm (lens) | 26mm (lens) |
| Sensor size | 1/2.55" inches | 1/1.33" inches |
| Pixel size | 1.4µm pixel | 1.8µm pixel |
| Autofocus | PDAF on back camera and autofocus front camera | PDAF: phase detection autofocus on both cameras |
| Touch focus | Supported | Supported |
| Image stabilization | OIS: Optical 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 | Supported | Supported |
| HDR | HDR photo/video on both cameras | HDR photo/video on both cameras |
| Camera extras | feature not registered | 4K@60fps 1080p@240fps 720p@960fps |
📸 Front camera | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Front camera (secondary) | 8 megapixels | 40 megapixels |
| Front camera resolution | 3264x2448 pixels | 7296x5472 pixels |
| Video recording (secondary) | 2K UHD (2560x1440) | 4K UHD (3840x2160) |
| Front flash | Not supported | Not supported |
| Focal aperture | f/1.7 (aperture) | f/2.2 (aperture) |
| Focal length | 25mm (lens) | 26mm (lens) |
| Sensor size | 1/3.6" inches | 1/2.8" inches |
| Pixel size | 1.22µm pixel | 0.7µm pixel |
🔉 Sound and multimedia | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Loudspeaker | Supported | 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, DivX, XviD | MP4, H.265, H.264, H.263, XviD, MKV |
| Audio formats | MP3, WAV, eAAC+, FLAC | MP3, WAV, WMA, eAAC+, FLAC |
🔌 Connectivity | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| USB | USB 3.1 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 | Supported | Supported |
| GPS | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou |
| NFC | Supported | Supported |
| Infrared port | Not supported | Not supported |
🧭 Sensors | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Sensors | Accelerometer Ambient light sensor ANT+ Barometer Compass Face unlock Fingerprint sensor (rear-mounted) Gyroscope Hall effect Heart rate Iris scanner Proximity sensor SpO2 | 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 | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| Battery type | Li-Ion: lithium-ion (Non removable) | LiPo: li-ion polymer (Non removable) |
| Battery capacity | 3500 mAh | 5000 mAh |
| Charger, watts | 15W (9V/1.67A) Wired fast charging Quick Charge 2 | 25W Wired fast charging USB Power Delivery 3.0 |
| Inductive / wireless charging | Qi wireless charging (Qi/PMA) | 15W Qi wireless charging (Qi/PMA) 4.5W Reverse wireless charging |
| Talk time autonomy | 34 hours (1.4 days) | feature not registered |
| Standby | 343 hours (14.3 days) | feature not registered |
➕ Other features | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 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: Black, Silver, Blue, Gold, Orchid Gray • Samsung DeX (desktop experience) • Curved edge screen • Corning Gorilla Glass 5 back panel • Samsung Gear VR compatible • Samsung Pay • 32bit/192kHz audio | • Colors: Phantom Black, Silver, Titanium, Navy, Brown • Samsung Pay (Visa, MasterCard) • Samsung DeX • Stylus pen support |
☢️ Radiation rate | ||
| Galaxy S8 Plus (SM-G955U) | Galaxy S21 Ultra (SM-G998N 512GB) | |
| SAR 1.6W/kg (USA, Mexico, etc.) | 0.46W/kg (head), 1.01W/kg (body) | 0.489W/kg (head), 1.1W/kg (body) |
| SAR 2W/kg (Europe, UK, etc.) | feature not registered | feature not registered |