Two devices. One clear decision.

LAUNCH DATE3 fields

Specification	Galaxy S21	Poco M8
Announced	January 29, 2021	8 January 2026 (manufacturer launch date)
Released	2021-01-29	8 January 2026 (launch market; local availability varies)
Status	Available	Released

NETWORK6 fields

Specification	Galaxy S21	Poco M8
2G Bands	GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2	GSM: B2/3/5/8
3G Bands	HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100; CDMA2000 1xEV-DO	WCDMA:B1/2/4/5/6/8/19
4G LTE	1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 38, 39, 40, 41, 46, 48, 66, 71 - SM-G991U1; 1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 32, 38, 39, 40, 41, 66 - SM-G991B	LTE FDD: B1/2/3/4/5/7/8/18/19/20/26/28/66/71; LTE TDD: B38/40/41/42/48
5G	2, 5, 25, 41, 66, 71, 260, 261 SA/NSA/Sub6/mmWave - SM-G991U1; 1, 3, 5, 7, 8, 20, 28, 38, 40, 41, 66, 77, 78 SA/NSA/Sub6 - SM-G991B	n1/2/3/5/7/8/20/28/38/40/41/48/66/71/77/78
Speed	LTE, 5G	LTE, 5G
Technology	5G/4G/LTE/GSM	5G / 4G / 3G / 2G

BODY5 fields

Specification	Galaxy S21	Poco M8
Build	Glass front (Gorilla Glass Victus), plastic back, aluminum frame	Composite back; plastic and aluminum-alloy die-cast mid-frame
Dimensions	151.7 x 71.2 x 7.9 mm (5.97 x 2.80 x 0.31 in)	164 x 75.42 x 7.35 mm
IP Rating	IP68 dust/water resistant (up to 1.5m for 30 min)	IP66
SIM	Nano-SIM + eSIM Nano-SIM + Nano-SIM + eSIM (max 2 at a time)	Dual nano-SIM, dual standby; second slot shared with microSD; no eSIM
Weight	169 g (Sub6), 171 g (mmWave) (5.96 oz)	178g

DISPLAY9 fields

Specification	Galaxy S21	Poco M8
Brightness	1300 nits (peak)	Brightness: 3200 nits peak brightness, 800 nits (typ)
Color	—	Color depth: 12-bit (68.7 billion colors); DCI-P3 wide color gamut
Features	—	Always-on display; sunlight and reading modes; DC/high-frequency PWM dimming; no HDR display
Protection	Corning Gorilla Glass Victus	Gorilla Glass 7i / Panda Glass 1711 (manufacturer FAQ lists alternative glass suppliers)
Refresh Rate	120Hz	Up to 120Hz
Resolution	1080 x 2400 pixels, 20:9 ratio (~421 ppi density)	1080 x 2392 pixels (~388 ppi density)
Screen-to-body	~87.2%	92%
Size	6.2 inches, 94.1 cm2 (~87.2% screen-to-body ratio)	6.77"
Type	Dynamic AMOLED 2X, 120Hz, HDR10+, 1300 nits (peak)	AMOLED

PLATFORM4 fields

Specification	Galaxy S21	Poco M8
CPU	Octa-core (1x2.9 GHz Cortex-X1 & 3x2.80 GHz Cortex-A78 & 4x2.2 GHz Cortex-A55) - International Octa-core (1x2.84 GHz Cortex-X1 & 3x2.42 GHz Cortex-A78 & 4x1.80 GHz Cortex-A55) - USA/China	Octa-core Arm Cortex-A78 + Cortex-A55; up to 2.4 GHz
Chipset	Exynos 2100 (5 nm) - International / Qualcomm SM8350 Snapdragon 888 5G (5 nm) - USA/China	Snapdragon 6 Gen 3
GPU	Mali-G78 MP14 - International Adreno 660 - USA/China	Qualcomm Adreno A710
OS	Android 11, up to 4 major Android upgrades, One UI 6.1	Android 15 with Xiaomi HyperOS 2 at launch

MEMORY5 fields

Specification	Galaxy S21	Poco M8
Card slot	No	Expandable storage up to 1TB
Internal	128GB, 256GB	256GB / 512GB
RAM	6GB RAM, 8GB RAM	8 GB / 12 GB (availability varies by region)
Storage Type	—	LPDDR4X + UFS2.2
Storage/RAM variants	128GB, 256GB; 6GB RAM, 8GB RAM	256GB / 512GB; 8 GB / 12 GB (availability varies by region) RAM

MAIN CAMERA3 fields

Specification	Galaxy S21	Poco M8
Features	LED flash, auto-HDR, panorama	Single LED flash; HDR photos; main-camera autofocus
MAIN CAMERA	12 MP, f/1.8, 26mm (wide), 1/1.76", 1.8µm, dual pixel PDAF, OIS 64 MP, f/2.0, 29mm (telephoto), 1/1.72", 0.8µm, PDAF, OIS, 1.1x optical zoom, 3x hybrid zoom 12 MP, f/2.2, 13mm, 120˚ (ultrawide), 1/2.55" 1.4µm, Super Steady video	50 MP main, f/1.8, autofocus; 2 MP depth, f/2.4, fixed focus
Video	8K@24fps, 4K@30/60fps, 1080p@30/60/120/240fps, HDR10+, stereo sound rec., gyro-EIS	4K at 30fps; 1080p at 30fps; 720p at 30fps

SELFIE CAMERA3 fields

Specification	Galaxy S21	Poco M8
Features	HDR	Fixed focus; HDR photos; EIS for video
Selfie camera	10 MP, f/2.2, 26mm (wide), 1/3.24", 1.22µm, dual pixel PDAF	20MP front camera, f/2.2
Video	4K@30/60fps, 1080p@30fps	1080p at 30fps; 720p at 30fps

SOUND3 fields

Specification	Galaxy S21	Poco M8
3.5mm jack	No	Yes
Dolby Atmos	—	Yes
Loudspeaker	Yes, with stereo speakers	Dual speakers

COMMUNICATION6 fields

Specification	Galaxy S21	Poco M8
Bluetooth	5.0, A2DP, LE	5.1
NFC	Yes	Yes
Positioning	GPS, GLONASS, BDS, GALILEO	GPS, GLONASS, Galileo, BDS
Radio	FM radio (Snapdragon model only; market/operator dependent)	No FM radio
USB	USB Type-C 3.2, OTG	USB Type-C 2.0; OTG; no DisplayPort Alt Mode
WLAN	Wi-Fi 802.11 a/b/g/n/ac/6, dual-band, Wi-Fi Direct	Wi-Fi 802.11a/b/g/n/ac; 2.4 GHz and 5 GHz; Wi-Fi Direct

FEATURES3 fields

Specification	Galaxy S21	Poco M8
Ai	—	Google Gemini, Circle to search with Google; AI Erase, AI Remove Reflection, AI Sky, AI Bokeh, AI Beautify
Satellite	—	No satellite communication
Sensors	Fingerprint (under display, ultrasonic), accelerometer, gyro, proximity, compass, barometer	Virtual proximity sensor; Ambient light sensor; Accelerometer; Electronic compass; IR blaster; Gyroscope

BATTERY3 fields

Specification	Galaxy S21	Poco M8
Capacity	4000 mAh	5520mAh (typ)
Charging Type	25W wired, PD3.0 15W wireless (Qi) 4.5W reverse wireless	45W turbo charging; Up to 18W reverse charging
Type	Li-Ion 4000 mAh	Silicon-anode battery; non-removable

ADDITIONAL INFORMATION6 fields

Specification	Galaxy S21	Poco M8
Colors	Phantom Gray, Phantom White, Phantom Violet, Phantom Pink	Black; Silver; Green
Compatibility	—	Global POCO M8 5G specification; nano-SIM + hybrid nano-SIM/microSD slot. Available configurations and network support vary by region.
Cooling	—	No dedicated cooling system, according to Xiaomi’s model-specific FAQ
Launch Price (USD)	$250.00 (reference only — see Price in Nigeria above for the actual retail price)	—
Models	SM-G991B, SM-G991B/DS, SM-G991U, SM-G991U1, SM-G991W, SM-G991N, SM-G9910, SM-G991Q, SCG09	Region-specific variants
Price in Nigeria	₦382,500	₦380,000

SECURITY1 field

Specification	Galaxy S21	Poco M8
Security	Biometric security: Fingerprint (under display, ultrasonic).	In-screen fingerprint sensor; AI face unlock