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Xiaomi Redmi Note 9S vs Samsung Galaxy A51

Here we compared two mid-range smartphones: the 6.67-inch Xiaomi Redmi Note 9S (with Qualcomm Snapdragon 720G) that was released on March 23, 2020, against the Samsung Galaxy A51, which is powered by Exynos 9 Octa 9611 and came out 4 months before. On this page, you will find tests, full specs, strengths, and weaknesses of each of the gadgets.

Key differences

An overview of the main advantages of each smartphone
Reasons to consider the Xiaomi Redmi Note 9S
  • Shows 48% longer battery life (127 vs 86 hours)
  • Comes with 1020 mAh larger battery capacity: 5020 vs 4000 mAh
  • 45% better performance in AnTuTu Benchmark (279K versus 192K)
  • Faster storage type - UFS 2.1 versus UFS 2.0
  • More energy-efficient CPU – Snapdragon 720G
  • 64% faster in single-core GeekBench 5 test: 582 and 354 points
  • Has a built-in infrared port
Reasons to consider the Samsung Galaxy A51
  • Delivers 9% higher maximum brightness (638 against 585 nits)
  • More recent OS version: Android 11 versus 10
  • Super AMOLED display (versus competitor's IPS LCD)
  • Supports Dolby Atmos sound technology
  • Weighs 38 grams less
  • The front-facing camera can record video at 4K

Review

Display
Screen quality, color accuracy, brightness
Performance
CPU/GPU performance in apps and games
Battery
Battery life, charging type and speed
Camera
Photo and video recording quality
Connectivity
Networks, ports, data transmission
NanoReview score
Final comparison evaluation

Value for money

You can enter your local price of these phones (in USD or any other currency) and click on the "Calculate" button to see which one has a better value for money.
Price

Tests and specifications

Comparison table of technical specifications and tests

Display

Type IPS LCD Super AMOLED
Size 6.67 inches 6.5 inches
Resolution 1080 x 2400 pixels 1080 x 2400 pixels
Aspect ratio 20:9 20:9
PPI 395 ppi 405 ppi
Refresh rate 60 Hz 60 Hz
HDR support Yes, HDR10 No
Screen protection Corning Gorilla Glass 5 Corning Gorilla Glass 3
Screen-to-body ratio 84.5% 87.4%
Display features - - Always-On Display
Display tests
RGB color space 114.9% 98.8%
PWM Not detected 242 Hz
Response time 34 ms 25 ms
Contrast 1111:1 ∞ Infinity
Max. Brightness
585 nits
638 nits
Sources: NotebookCheck [1], [2]

Design and build

Height 166 mm (6.54 inches) 158.5 mm (6.24 inches)
Width 77 mm (3.03 inches) 73.6 mm (2.9 inches)
Thickness 8.8 mm (0.35 inches) 7.9 mm (0.31 inches)
Weight 210 gramm (7.41 oz) 172 gramm (6.07 oz)
Waterproof No No
Rear material Glass Plastic
Frame material Plastic Plastic
Colors White, Black, Blue White, Black
Fingerprint scanner Yes, in home button Yes, in-display
Screen-to-body ratio
87.4%

Performance

Tests of Xiaomi Redmi Note 9S and Samsung Galaxy A51 in the benchmarks
SoC
Chipset Qualcomm Snapdragon 720G Samsung Exynos 9 Octa 9611
Max. clock 2300 MHz 2300 MHz
CPU cores 8 (2 + 6) 8 (4 + 4)
Architecture - 6 cores at 1.8 GHz: Kryo 465 Silver (Cortex-A55)
- 2 cores at 2.3 GHz: Kryo 465 Gold (Cortex-A76)
- 4 cores at 1.7 GHz: Cortex-A53
- 4 cores at 2.3 GHz: Cortex-A73
L3 cache 1 MB -
Lithography process 8 nanometers 10 nanometers
Graphics Adreno 618 Mali-G72 MP3
GPU clock 750 MHz 850 MHz
FLOPS ~435 GFLOPS ~259 GFLOPS
Memory
RAM size 4 GB 4, 6 GB
Memory type LPDDR4X LPDDR4X
Memory clock 2133 MHz 1866 MHz
Channels 2 2
Storage
Storage size 64 GB 64, 128 GB
Storage type UFS 2.1 UFS 2.0
Memory card MicroSD MicroSD
Memory card max. size Up to 512 GB Up to 512 GB

Benchmarks

Geekbench 5 (Single-Core)
582
Geekbench 5 (Multi-Core)
1764
1302
AnTuTu Benchmark 7
AnTuTu Benchmark 8
279535
192153

Software

Operating system Android 10.0 Android 10 (Can be upgraded to Android 11)
ROM MIUI 12 One UI 3.0
OS size 18 GB 23 GB

Battery

Specifications
Capacity 5020 mAh 4000 mAh
Charge power 18 W 15 W
Battery type Li-Po Li-Po
Replaceable No No
Wireless charging No No
Reverse charging No No
Fast charging Yes (50% in 50 min) Yes (40% in 35 min)
Full charging time 2:30 hr 1:50 hr

Battery life tests

Web browsing (Wi-Fi)
19:12 hr
13:21 hr
Watching videos (Player)
16:30 hr
14:22 hr
Talk (3G)
41:30 hr
21:51 hr

Camera

Specs and camera test of smartphones
Main camera
Matrix 48 megapixels 48 megapixels
Image resolution 8000 x 6000 8000 x 6000
Zoom Digital Digital
Flash LED LED
Stabilization Digital Digital
8K video recording No No
4K video recording Up to 30FPS Up to 30FPS
1080p video recording Up to 60FPS Up to 30FPS
Slow motion 960 FPS (1080p) 960 FPS (720p)
Angle of widest lens 119° 120°
Lenses 4 (48 MP + 8 MP + 5 MP + 2 MP) 4 (48 MP + 12 MP + 5 MP + 5 MP)
Wide (main) lens - 48 MP
- Aperture: f/1.8
- Focal length: 26 mm
- Pixel size: 0.8 micron
- Sensor: 1/2", Samsung S5KGM2 (ISOCELL CMOS)
- Phase autofocus
- 48 MP
- Aperture: f/2.0
- Focal length: 26 mm
- Pixel size: 0.8 micron
- Sensor: 1/2", Samsung S5KGM2 (ISOCELL CMOS)
- Phase autofocus
Ultra-wide lens - 8 MP
- Aperture: f/2.2
- Focal length: 13 mm
- Pixel size: 1.12 micron
- Sensor: 1/4.0", Omnivision OV8856
- 12 MP
- Aperture: f/2.2
- Focal length: 13 mm
- Pixel size: 1.12 micron
Macro lens - 5 MP
- Aperture: f/2.4
- Pixel size: 1.12 micron
- 5 MP
- Aperture: f/2.4
- Focal length: 40 mm
- Pixel size: 1.12 micron
Depth lens - 2 MP
- Aperture: f/2.4
- Pixel size: 1.75 micron
- 5 MP
- Aperture: f/2.2
- Pixel size: 1.12 micron
- Sensor: 1/5.0" (CMOS)
Camera features - Bokeh mode
- Pro mode
- Bokeh mode
- Pro mode
Selfie camera
Megapixels 16 megapixels 32 megapixels
Image resolution 4920 x 3264 6560 x 4928
Aperture f/2.5 f/2.2
Focal length - 26 mm
Pixel size 1 microns 0.8 microns
Sensor type CMOS ISOCELL CMOS
Sensor size 1/3.06" 1/2.8"
Video resolution 1080p (Full HD) при 30 FPS 2160p (4K) при 30 FPS

Connectivity

Wi-Fi standard Wi-Fi 5 (802.11 b/g/n/ac) Wi-Fi 5 (802.11 b/g/n/ac)
Wi-Fi features - Dual Band
- Wi-Fi Direct
- Wi-Fi Hotspot
- Wi-Fi Display
- Dual Band
- Wi-Fi Direct
- Wi-Fi Hotspot
- Wi-Fi Display
Bluetooth version 5 5
Bluetooth features LE, HID, A2DP PBAP/PAB, PAN, OPP, MAP, HSP, HID, HFP, DIP, AVRCP, A2DP
USB type USB Type-C USB Type-C
USB version 2 2
USB features - Charging
- USB-Storage mode
- OTG
- Charging
- USB-Storage mode
- OTG
GPS GPS, GLONASS, Beidou, Galileo, NAVIC GPS, GLONASS, Beidou, Galileo
NFC* No Yes
Infrared port Yes No
Network
Number of SIM* 2 2
Type of SIM card Nano Nano
Multi SIM mode Standby Standby
eSIM support* No No
Hybrid slot No No
LTE Cat* 12 12
5G support No No

Sound

Speakers Mono Mono
Headphone audio jack Yes Yes
FM radio Yes Yes
Dolby Atmos No Yes
Speakers test
Max. loudness
81.7 dB

Other

Category Mid-range Mid-range
Announced March 2020 December 2019
Release date April 2020 December 2019
Launch price ~ 225 USD ~ 250 USD
SAR (head) 0.72 W/kg 0.596 W/kg
SAR (body) 0.98 W/kg 1.45 W/kg
Sensors - Proximity sensor
- Gyroscope
- Accelerometer
- Ambient light sensor
- Compass
- Fingerprint
- Proximity sensor
- Gyroscope
- Accelerometer
- Ambient light sensor
- Compass
- Fingerprint
*Disclaimer! NFC, GSM network support, and some other specs can be different depending on the country.

Conclusion

If the performance and battery life are more important to you, then choose the Xiaomi Redmi Note 9S. But if the software, design, and sound are more of a priority – go for the Samsung Galaxy A51.

Cast your vote

So, which phone would you choose?
631 (80.3%)
155 (19.7%)
Total votes: 786

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