Xiaomi Redmi Note 4X vs Google Pixel 4a vs Samsung Galaxy A51

Compare phone and tablet specifications of up to three devices at once.

Display

Size:

5.5 inches
5.8 inches
6.5 inches

Resolution:

1920 x 1080 pixels, 401 PPI
2340 x 1080 pixels, 19.5:9 ratio, 444 PPI
2400 x 1080 pixels, 20:9 ratio, 405 PPI

Technology:

IPS LCD
OLED
Super AMOLED

Screen-to-body:

72.78 %
82.53 %
87.37 %

Colors:

16 777 216

Touchscreen:

Capacitive, Multi-touch

Features:

Ambient light sensor, Proximity sensor
60Hz refresh rate, HDR support, Scratch-resistant glass (Corning Gorilla Glass 3), Ambient light sensor, Proximity sensor
60Hz refresh rate, Scratch-resistant glass (Corning Gorilla Glass 3), Ambient light sensor, Proximity sensor

Hardware

System chip:

Qualcomm Snapdragon 625 8953
Qualcomm Snapdragon 730 SM7150-AA
Samsung Exynos 9611

Processor:

Octa-core, 2000 MHz, ARM Cortex-A53, 64-bit, 14 nm
Octa-core, 2200 MHz, Kryo 470, 64-bit, 8 nm
Octa-core, 2300 MHz, ARM Cortex-A73 and ARM Cortex-A53, 64-bit, 10 nm

GPU:

Adreno 506
Adreno 618
Mali-G72 MP3

RAM:

3GB DDR3
6GB LPDDR4
4GB LPDDR4

Internal storage:

32GB
128GB, not expandable
128GB, available to use: 105.9 GB

Storage expansion:

microSDXC up to 128 GB
microSDXC up to 512 GB

Device type:

Smartphone
Smartphone
Smartphone

OS:

Android (6.0 Marshmallow)
Android (11, 10)
Android (11, 10), Samsung One UI

Battery

Capacity:

4100 mAh
3140 mAh
4000 mAh

Type:

Li - Polymer, Not user replaceable
Li - Polymer, Not user replaceable
Li - Polymer, Not user replaceable

Battery life test results:

Charging:

USB Power Delivery
Fast charging

Max charge speed:

Wired: 18.0W

Camera

Rear:

Single camera
Single camera
Quad camera

Main camera:

13 MP (CMOS image sensor, PDAF)
12.2 MP (OIS, PDAF)
48 MP (PDAF)

Specifications:

Aperture size: F2.0
Aperture size: F1.7; Focal length: 27 mm; Sensor size: 1/2.55"; Pixel size: 1.4 μm
Aperture size: F2.0; Focal length: 26 mm; Sensor size: 1/2"; Pixel size: 0.8 μm

Second camera:

12 MP (Ultra-wide)

Specifications:

Aperture size: F2.2; Focal Length: 13 mm; Pixel size: 1.12 μm

Third camera:

5 MP (Macro)

Specifications:

Aperture size: F2.4; Focal Length: 40 mm

Fourth camera:

5 MP (Depth information)

Specifications:

Aperture size: F2.2; Sensor size: 1/5"; Pixel size: 1.12 μm

Video recording:

1920x1080 (Full HD) (30 fps), 1280x720 (HD) (120 fps)
3840x2160 (4K UHD) (30 fps), 1920x1080 (Full HD) (120 fps), 1280x720 (HD) (240 fps)
3840x2160 (4K UHD) (30 fps), 1920x1080 (Full HD) (120 fps), 1280x720 (HD) (240 fps)

Features:

Video calling, Video sharing
EIS
Hyperlapse, EIS

Front:

5 MP
8 MP
32 MP (HDR)

Video capture:

1920x1080 (Full HD)
1920x1080 (Full HD)

Design

Dimensions:

5.94 x 2.99 x 0.33 inches (151 x 76 x 8.45 mm)
5.67 x 2.73 x 0.32 inches (144 x 69.4 x 8.2 mm)
6.24 x 2.90 x 0.31 inches (158.5 x 73.6 x 7.9 mm)

Weight:

5.82 oz (165.0 g)
5.04 oz (143.0 g)
6.07 oz (172.0 g)

Materials:

Back: Metal
Back: Plastic; Frame: Plastic
Back: Plastic; Frame: Plastic

Biometrics:

Fingerprint (touch)
Fingerprint (touch)
2D Face unlock, In-screen fingerprint

Features:

Touch sensitive control keys

Keys:

Right: Volume control, Lock/Unlock key
Right: Volume control, Lock/Unlock key
Right: Volume control, Lock/Unlock key

Colors:

Black, Gold, Gray, Pink, Green
Just black
Prism Crush black, Prism Crush white, Prism Crush pink, Prism Crush blue

Cellular

LTE (FDD):

Bands 1(2100), 3(1800), 5(850), 7(2600)
Bands 1(2100), 2(1900), 3(1800), 4(AWS-1), 5(850), 7(2600), 8(900), 12(700 a), 13(700 c), 14(700 PS), 17(700 b), 18(800 Lower), 20(800 DD), 25(1900+), 26(850+), 28(700 APT), 29(700 d), 30(2300 WCS), 66(AWS-3), 71(600)
Bands 1(2100), 2(1900), 3(1800), 4(AWS-1), 5(850), 7(2600), 8(900), 12(700 a), 13(700 c), 14(700 PS), 20(800 DD), 25(1900+), 26(850+), 28(700 APT), 29(700 d), 30(2300 WCS), 66(AWS-3), 71(600)

LTE (TDD):

Bands 38(2600), 39(1900+), 40(2300), 41(2600+)
Bands 38(2600), 39(1900+), 40(2300), 41(2600+)
Bands 38(2600), 39(1900+), 41(2600+)

UMTS:

Bands 5(850), 8(900), 2(1900), 1(2100)
Bands 5(850), 8(900), 4(1700/2100), 2(1900), 1(2100)
Bands 5(850), 8(900), 4(1700/2100), 2(1900), 1(2100)

Data Speed:

LTE-A Cat 6 (300/50 Mbit/s), HSPA
LTE-A Cat 11 (600/75 Mbit/s), HSDPA+ (4G) 42.2 Mbit/s, HSUPA 5.76 Mbit/s
LTE-A, HSDPA+ (4G) 42.2 Mbit/s, HSUPA 5.76 Mbit/s

Dual SIM:

Shared with microSD
Yes

SIM type:

Nano SIM, Micro SIM
Nano SIM, eSIM
Nano SIM

HD Voice:

Yes

VoLTE:

Yes

Multimedia

Headphones:

3.5mm jack
3.5mm jack
3.5mm jack

Speakers:

Earpiece, Loudspeaker
Earpiece, Multiple speakers
Earpiece, Loudspeaker

Features:

Album art cover, Background playback
aptX, aptX-HD
Dolby Atmos

Screen mirroring:

Wireless screen share
Wireless screen share
Wireless screen share

Radio:

FM

Additional microphone(s):

for Noise cancellation
for Noise cancellation
for Noise cancellation

Connectivity & Features

Bluetooth:

4.2
5.1
5.0

Wi-Fi:

802.11 a, b, g, n, dual-band; Hotspot, Wi-Fi Direct
802.11 a, b, g, n, ac, dual-band; MIMO, Wi-Fi Direct, Hotspot
802.11 a, b, g, n, ac, dual-band; Wi-Fi Direct, Hotspot

USB:

microUSB, USB 2.0
Type-C (reversible), USB 3.1
Type-C (reversible), USB 2.0

Features:

Mass storage device, Charging
Charging
Charging, OTG

Location:

GPS, A-GPS, Glonass, BeiDou
GPS, A-GPS, Glonass, Galileo, Cell ID, Wi-Fi positioning
GPS, A-GPS, Glonass, Galileo, BeiDou, Cell ID, Wi-Fi positioning

Sensors:

Accelerometer, Gyroscope, Hall (for flip covers)
Accelerometer, Gyroscope, Compass, Barometer
Accelerometer, Gyroscope, Compass, Hall (for flip covers)

Other:

Infrared, VoIP, Tethering, Computer sync, OTA sync
NFC
NFC, ANT+

Hearing aid compatible:

M3, T4

Phone features

Notifications:

Haptic feedback

Other features:

Voice dialing, Voice commands, Voice recording

Regulatory Approval

FCC approval:

Date approved:

Jun 25, 2020
Nov 28, 2019

FCC ID value:

A4RG025J link
A3LSMA515FN link

Measured SAR:

Head:

1.18 W/kg
0.89 W/kg

Body:

1.19 W/kg
1.18 W/kg

Simultaneous Transmission:

1.59 W/kg
1.56 W/kg

Wireless Router:

1.00 W/kg
1.12 W/kg

Phablet:

2.76 W/kg

Buyers information

Price:

$ 145
$ 349
$ 400

User Manual:

This is the official Samsu​ng Galaxy A51 User Guide in English provided from the manufacturer.

In The Box:

18W USB-C power adapter, 1 m USB-C to USB-C cable (USB 2.0), Quick Start Guide, Quick Switch Adapter, SIM tool

Availability

Officially announced:

Feb 08, 2017
Aug 03, 2020
Dec 12, 2019
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