Samsung Galaxy S21 Ultra vs Xiaomi Poco X8 Pro Max Specs Comparison

Availability

Officially announced
Jan 14, 2021	Mar 17, 2026
Prices (MSRP)
12GB/128GB - $1200 | €1399 12GB/256GB - $1250 16GB/512GB - $1380	12GB/256GB - $469

Design

Dimensions
6.50 x 2.98 x 0.35 inches (~0.37 inches with camera bump) 165.1 x 75.6 x 8.9 mm (~9.4 mm with camera bump)	6.41 x 3.07 x 0.32 inches (~0.41 inches with camera bump) 162.9 x 77.9 x 8.2 mm (~10.30 mm with camera bump)
Weight
8.04 oz / 229.0 g Europe version - 227 g	7.69 oz / 218.0 g
Materials
Back: Glass (Corning Gorilla Glass Victus) Frame: Aluminum	Back: Glass Frame: Aluminum
Resistance
Water, Dust; IP68	Water, Dust; IP68
Biometrics
2D Face unlock, Ultrasonic in-screen fingerprint	Ultrasonic in-screen fingerprint
Keys
Right: Volume control, Lock/Unlock key	Right: Volume control, Lock/Unlock key
Colors
Phantom black, Silver

Display

Size
6.8-inch, 89.33% screen-to-body	6.8-inch, 90.22% screen-to-body
Type
Dynamic AMOLED, 120Hz, HDR, 1500 nits	AMOLED, 120Hz, 3500 nits
Resolution
3200x1440px, 20:9 ratio, 516 PPI	2772x1280px, 447 PPI
Protection
Corning Gorilla Glass Victus

PhoneArena Display Test

Bright Max (20% APL)
Untested	3362 (Excellent)
Bright Min
1.5 (Good)	1.9 (Good)

Learn more on our PhoneArena Display Test Results page.

Hardware

System chip
Snapdragon 888 SM8350 (5 nm) Europe version - Exynos 2100 S5E9840	MediaTek Dimensity 9500 (3 nm)
Processor
Octa-core 1x2.84GHz Kryo 680 3x2.42GHz Kryo 680 4x1.80GHz Kryo 680 Europe version - Octa-core, 1x2.91GHz Cortex-X1, 3x2.81G​Hz Cortex-A78, 4x2.2G​Hz Cortex-A55	Octa-core 1x4.21GHz C1-Ultra 3x3.5GHz C1-Premium 4x2.7 GHz C1-Pro
GPU
Adreno 660 Europe version - Mali-G78 MP14	Mali G1-Ultra
Memory
12GB (LPDDR5)/128GB (UFS 3.1) 12GB/256GB 16GB/512GB	12GB/256GB 12GB/512GB
Storage expansion
not expandable
OS
Android (14, 13, 12, 11)	Android (16)

PhoneArena Performance Test

GeekBench 6 Single
1117	2636
GeekBench 6 Multi
3312	8334
3D Mark High
1963	4194
3D Mark Low
1179	3416

Learn more on our PhoneArena Performance Test Results page.

Battery

Type
5000 mAh, Li - Polymer	8500 mAh, Si - Carbon
Charging
Qualcomm Quick Charge 2.0, USB Power Delivery, Samsung Adaptive Fast Charging Qi and Powermat wireless charging, Reverse wireless charging
Charge speed
Wired: 25.0W Wireless: 15.0W	Wired: 100.0W

PhoneArena Battery Tests

Battery Life Estimate

6h 15min

Browsing

14h 43min

Video

8h 52min

Gaming

8h 40min

Battery Life Estimate

10h 21min

Browsing

26h 6min

Video

15h 26min

Gaming

9h 55min

Learn more on our PhoneArena Battery Test Results page

Camera

Rear
Quad camera	Dual camera
Main camera
108 MP (OIS, Laser and PDAF) Aperture size: F1.8 Focal length: 24 mm Sensor size: 1/1.33" Pixel size: 0.8 μm	50 MP (OIS, PDAF) Aperture size: F1.5
Second camera
12 MP (Ultra-wide, PDAF) Aperture size: F2.2 Focal Length: 13 mm Sensor size: 1/2.55" Pixel size: 1.4 μm	8 MP (Ultra-wide) Aperture size: F2.2
Third camera
10 MP (Telephoto, OIS, PDAF) Optical zoom: 3.0x Aperture size: F2.4 Focal Length: 70 mm Sensor size: 1/3.2" Pixel size: 1.22 μm
Fourth camera
10 MP (Telephoto, Periscope, OIS, PDAF) Optical zoom: 10.0x Aperture size: F2.4 Focal Length: 70 mm Sensor size: 1/3.2" Pixel size: 1.22 μm
Flash
LED	LED
Video recording
8K UHD (24 fps), 4K UHD (60 fps), 1080p (240 fps), 720p (960 fps) OIS, HDR, Hyperlapse, Video light, EIS	Yes
Front
40 MP (PDAF, HDR) Video capture: 4K UHD (60 fps)	20 MP

Connectivity & Features

Bluetooth
5.1	Yes
WLAN
Wi-Fi 6,dual-band MIMO, Wi-Fi Direct, Hotspot 802.11 a, b, g, n, ac, ax	Wi-Fi 6,Wi-Fi 7 Wi-Fi Direct, Hotspot
USB
Type-C, USB 3.2	Type-C
Sensors
Accelerometer, Gyroscope, Compass, Hall (for flip covers), Barometer, Ambient light sensor, Proximity sensor	Accelerometer, Gyroscope, Compass, Ambient light sensor, Proximity sensor
Hearing aid compatible
M3/T3
Location
GPS, A-GPS, Glonass, Galileo, BeiDou, Cell ID, Wi-Fi positioning	GPS, A-GPS, Glonass, Galileo, BeiDou, Cell ID, Wi-Fi positioning
Other
NFC, ANT+	NFC

Multimedia

Headphones
No 3.5mm jack	No 3.5mm jack
Speakers
Earpiece, Multiple speakers	Earpiece, Multiple speakers
Features
32-Bit DAC, Dolby Atmos, aptX, Dolby Digital, Dolby Digital Plus
Screen mirroring
	Wireless screen share
Additional microphone(s)
	Noise cancellation

Cellular

5G Bands
n2, n5, n12, n25, n41, n66, n71, n77, n260, n261, SA, NSA, Sub-6, mmWave	5G Ready
LTE Bands
1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 66, 71
TDD Bands
38, 39, 40, 41, 46, 48
3G Bands
1, 2, 4, 5, 8
Data Speed
LTE-A Pro Cat 20 (2000/150 Mbit/s)
SIM type
Nano SIM	Nano SIM

Regulatory Approval

FCC approval
Date approved: Dec 22, 2020 FCC ID value: A3LSMG998U
Measured SAR
Head: 0.77 W/kg Body: 1.02 W/kg Simultaneous Transmission: 1.59 W/kg Wireless Router: 1.16 W/kg Phablet: 3.15 W/kg

Alternative variants

with 256GB storage

Memory	256GB
Colors	Phantom black
Prices (MSRP)	$1250

with 512GB storage

Memory	16GB/512GB
Colors	Phantom black
Prices (MSRP)	$1380

for Europe

System chip	Samsung Exynos 2100 (5 nm)
Processor	Octa-core 1x2.91GHz Cortex-X1 3x2.81G​Hz Cortex-A78 4x2.2G​Hz Cortex-A55
GPU	Mali G78 MP14
Weight	8.01 oz / 227.0 g
5G Bands	SA, NSA, Sub-6
FCC approval	Date approved: Dec 22, 2020 FCC ID value: A3LSMG998B
Measured SAR	Head: 0.16 W/kg Body: 0.72 W/kg Simultaneous Transmission: 1.59 W/kg Wireless Router: 1.34 W/kg Phablet: 3.86 W/kg

Discover more

Full Specs Samsung Galaxy S21 Ultra Specs PA Review Samsung Galaxy S21 Ultra Review

Full Specs Xiaomi Poco X8 Pro Max Specs PA Review Xiaomi Poco X8 Pro Max Review