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Samsung Galaxy A51 SM-A515F/DS Dual SIM 4GB RAM 128GB vs. Samsung Galaxy S21 SM-G991B 5G Dual SIM 8GB RAM 128GB + 1
Built-in camera
Yes
Yes
Yes
Front camera
Yes
Yes
Yes
Effective pixels front camera
32 megapixels
10 megapixels
32 megapixels
Number of front cameras
1 ​
1 ​
1 ​
Camera features
Autofocus, Built-in flash/lamp, Electronic image stabilization (EIS)
Autofocus, Built-in flash/lamp, Optical image stabilization (OIS), Electronic image stabilization (EIS), Optical zoom
Autofocus, Built-in flash/lamp, Electronic image stabilization (EIS)
Effective pixels
48 megapixels
64 megapixels
64 megapixels
Maximum lens aperture
2
1.8
1.8
Number of rear cameras
4 ​
3 ​
4 ​
Sensor format
1/2"
1/1.76"
1/1.72"
Video recording
Yes
Yes
Yes
Max frame rate (highest resolution)
24 fps
Max frame rate (regardless of res.)
240 fps
960 fps
240 fps
Max resolution (highest frame rate)
1920x1080 (HD 1080) pixels
1280x720 (HD 720) pixels
1920x1080 (HD 1080) pixels
Maximum resolution (video)
3840x2160 (4K Ultra HD) pixels
7680x4320 (8K Ultra HD) pixels
3840x2160 (4K Ultra HD) pixels
2G (GSM)
Yes
Yes
Yes
3G (UMTS)
Yes
Yes
Yes
HSPA+
Yes
Yes
Yes
4G (LTE)
Yes
Yes
Yes
4G: Speed (down/up)
Cat.20/18: 2000/200 Mbit/s
5G (NR)
No
Yes
No
Frequency range (5G)
FR1 (Sub-6 GHz)
Bluetooth
Yes
Yes
Yes
Bluetooth codec
SBC
aptX, LDAC, SBC
Bluetooth profile
A2DP, AVRCP
A2DP
A2DP
Bluetooth version
5.0
5.1
5.0
Built-in navigation system
Yes
Yes
Yes
Type of navigation system
GPS, A-GPS, BeiDou, Galileo, GLONASS
GPS, A-GPS, BeiDou, Galileo, GLONASS
GPS, A-GPS, BeiDou, Galileo, GLONASS
NFC
Yes
Yes
Yes
Wireless network (Wi-Fi)
Yes
Yes
Yes
Wireless networking standard
802.11a, 802.11b, 802.11g, 802.11n (Wi-Fi 4), 802.11ac (Wi-Fi 5)
802.11a, 802.11b, 802.11g, 802.11n (Wi-Fi 4), 802.11ac (Wi-Fi 5), 802.11ax (Wi-Fi 6)
802.11a, 802.11b, 802.11g, 802.11n (Wi-Fi 4), 802.11ac (Wi-Fi 5)
Data connector
USB
USB
USB
Type of USB connector
USB (Type C)
USB (Type C)
USB (Type C)
USB On-The-Go (OTG)
Yes
Yes
Yes
USB version
2.0
3 (Gen 1)
2.0
Headphone output (2.5/3.5 mm)
Yes
No
Yes
Type of connection
3.5 mm
3.5 mm
Colour
Black, Silver, Blue, White, Green, Grey, Pink
Black, Silver, White, Grey, Purple, Pink
Black, Silver, Blue, White
Developed especially for seniors
No
No
No
Physical keyboard/numpad
No
No
No
Dimensions (WxHxD)
Depth
7.9 mm
7.9 mm
7.7 mm
Height
158.5 mm
151.7 mm
163.6 mm
Width
73.6 mm
71.2 mm
76 mm
Product weight
172 g
169 g
179 g
Built-in sensors
Proximity sensor, Accelerometer, Gyroscope
Proximity sensor, Accelerometer, Gyroscope, Barometer
Proximity sensor, Accelerometer, Gyroscope, Barometer
Built-in wireless charging
No
Yes
No
Wireless standard
QI, PMA
Dual SIM card support
Yes
Yes
Yes
Hybrid Dual Sim
No
No
Type of Dual SIM
Dual SIM cards
Nano SIM/eSIM
Dual SIM cards
Features
FM radio, Shock resistant, ANT+
Shock resistant, ANT+, Built-in stereo speakers, Hearing Aid Compatible, Ultra-wideband (UWB)
FM radio, ANT+
Security
Fingerprint reader, Face scanner
Fingerprint reader, Face scanner
Fingerprint reader, Face scanner
SIM card
Nano sim
Nano sim
Nano sim
Supports fast charging
Yes
Yes
Yes
Water resistant
No
Yes
No
IP code (level of dust/water resistance)
IP68
Series
Galaxy A51
Samsung Galaxy S21
Galaxy A70
Aspect ratio
20:9
20:9
20:9
Display features
Scratch resistant display
Scratch resistant display, HDR, 120Hz refresh rate
Scratch resistant display, HDR
Display technology
OLED (AMOLED)
OLED (AMOLED)
OLED (AMOLED)
Display
Colour
Colour
Colour
Number of colours
16 777 216 colours
16 777 216 colours
16 777 216 colours
Pixel density
405 PPI
421 PPI
393 PPI
Screen resolution (HxV)
1080x2400 pixels
1080x2400 pixels
1080x2400 pixels
Screen size
6.5 inches
6.2 inches
6.7 inches
Touchscreen
Yes
Yes
Yes
Material (body/chassis)
Glass, Plastic
Aluminium, Plastic
Glass, Plastic
RAM size
4GB
8GB
6GB
Keyword
Release year
2019
2021
2020
Battery capacity
4000 mAh
4000 mAh
4500 mAh
Exchangeable battery
No
No
No
Graphics processor (GPU)
Yes
Yes
Yes
Graphics processor type
ARM Mali-G72 MP3
ARM Mali-G78 MP14
Adreno 618
Processor core type
8 (Octa) Core
8 (Octa) Core
8 (Octa) Core
Processor speed
2.3 GHz
2.9 GHz
2.2 GHz
SoC/CPU (System on Chip)
Samsung Exynos 9 Octa (9611)
Samsung Exynos 2100
Qualcomm Snapdragon 730 SDM730
Support for alternative firmware
Memory card reader
Yes
No
Yes
Compatible memory cards
microSD, microSDHC, microSDXC
microSD, microSDHC, microSDXC
Maximum memory card size
512GB
512GB
Storage space
128 GB
128 GB
128 GB