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LG K51S Smartphone Review – Too little, too late?

Faster would be appropriate. Will even an inexpensive smartphone like the LG K51S still be allowed to bring Android 9 in 2020? And is it worthwhile to buy it thanks to the quadruple camera and NFC, despite the older operating system? These are just two of the questions we want to answer in this review of the LG cell phone.
Florian Schmitt, 👁 Florian Schmitt (translated by DeepL / Ninh Duy),
LG K51S
LG K51S (K Series)
Processor
Mediatek Helio P35 MT6765 8 x 2.3 GHz, Cortex-A53
Graphics adapter
Memory
3072 MB 
Display
6.55 inch 20:9, 1600 x 720 pixel 270 PPI, Capacitive, IPS, glossy: yes, 60 Hz
Storage
64 GB eMMC Flash, 64 GB 
, 48 GB free
Connections
1 USB 2.0, Audio Connections: 3.5mm, Card Reader: microSD up to 2 TB, 1 Fingerprint Reader, NFC, Brightness Sensor, Sensors: Acceleration sensor, Proximity sensor, Compass
Networking
802.11 b/g/n (b/g/n = Wi-Fi 4), Bluetooth 5.0, 2G (850/​900/​1800/​1900), 3G (B1/​B2/​B5/​B8), 4G (B1/​B3/​B7/​B8/​B20/​B28) , Dual SIM, LTE, GPS
Size
height x width x depth (in mm): 8.2 x 165.2 x 76.7 ( = 0.32 x 6.5 x 3.02 in)
Battery
4000 mAh Lithium-Ion
Operating System
Android 9.0 Pie
Camera
Primary Camera: 32 MPix Phase comparison AF, LED flash, video @1080p/30fps (camera 1); 5.0MP, wide angle lens (camera 2); 2.0MP, macro lens (camera 3); 2.0MP, depth of field (camera 4)
Secondary Camera: 13 MPix
Additional features
Speakers: Mono loudspeaker at the lower edge, Keyboard: Virtual, Charger, USB cable, silicone bumper, 24 Months Warranty, MIL-STD-810G certified; SAR value: 0.501W/kg (head), 1.335W/kg (body);, fanless
Weight
195 g ( = 6.88 oz / 0.43 pounds), Power Supply: 53 g ( = 1.87 oz / 0.12 pounds)
Price
209 Euro
Note: The manufacturer may use components from different suppliers including display panels, drives or memory sticks with similar specifications.

 

Comparison devices

Bewertung
Rating Version
Datum
Modell
Gewicht
Laufwerk
Groesse
Aufloesung
Preis ab
76 %7
09/2020
LG K51S
Helio P35 MT6765, PowerVR GE8320
195 g64 GB eMMC Flash6.55"1600x720
76 %7
12/2019
LG K50S
Helio P22 MT6762, PowerVR GE8320
194 g32 GB eMMC Flash6.50"1560x720
80 %7
09/2020
Samsung Galaxy M21
Exynos 9611, Mali-G72 MP3
188 g64 GB UFS 2.1 Flash6.40"2340x1080
77 %7
08/2020
Honor 9X Lite
Kirin 710, Mali-G51 MP4
188 g128 GB eMMC Flash6.50"2340x1080

Case, equipment and operation - Eye-catching photo module

The LG K51S draws attention to itself with its back: The wide, but in the height very narrow camera module is definitely an eye-catcher. You can also customize the color selection thanks to the red or blue housing. For those who prefer a more reserved look, there is also a simple dark gray.

The workmanship looks good, material transitions are hardly noticeable and the stable smartphone housing also reacts to pressure with stoic composure.

The fact that NFC is on board is already a plus, making mobile payment services easy to use. Even the modern USB-C connection is not yet standard on all smartphones in this price class. 64 GB eMMC flash as mass storage and only 3 GB RAM, however, are somewhat stingy. In our tests with the reference router Netgear Nighthawk AX12, the WLAN also proved to be quite slow in a class comparison.

It's annoying that LG still relies on the older Android 9, for the predecessor LG K50S an update is only planned for the next months, if it stays at this speed, buyers of the LG K51S have to wait another year for an operating system update, then Android 10 would already be two years old again. Also the security patches are already clearly outdated at the time of testing.

The fingerprint sensor on the back can be easily felt and reacts quickly to a touch. The unlocking also works with only a short waiting time.

Size comparison

165.8 mm / 6.53 inch 77.5 mm / 3.05 inch 8.2 mm / 0.3228 inch 194 g0.4277 lbs165.2 mm / 6.5 inch 76.7 mm / 3.02 inch 8.2 mm / 0.3228 inch 195 g0.4299 lbs160.4 mm / 6.31 inch 76.6 mm / 3.02 inch 7.8 mm / 0.3071 inch 188 g0.4145 lbs159 mm / 6.26 inch 75.1 mm / 2.96 inch 8.9 mm / 0.3504 inch 188 g0.4145 lbs
Networking
iperf3 Client (receive) TCP 1 m 4M x10
Samsung Galaxy M21
802.11 a/b/g/n/ac
332 (231min - 352max) MBit/s ∼100% +437%
LG K50S
802.11 a/b/g/n/ac
197 (144min - 211max) MBit/s ∼59% +219%
Honor 9X Lite
802.11 a/b/g/n/ac
153 (106min - 195max) MBit/s ∼46% +148%
LG K51S
802.11 b/g/n
61.8 (57min - 63max) MBit/s ∼19%
iperf3 Client (transmit) TCP 1 m 4M x10
Samsung Galaxy M21
802.11 a/b/g/n/ac
304 (285min - 323max) MBit/s ∼100% +453%
Honor 9X Lite
802.11 a/b/g/n/ac
196 (47min - 258max) MBit/s ∼64% +256%
LG K50S
802.11 a/b/g/n/ac
182 (147min - 215max) MBit/s ∼60% +231%
LG K51S
802.11 b/g/n
55 (51min - 69max) MBit/s ∼18%
010203040506070Tooltip
; iperf3 Client (receive) TCP 1 m 4M x10; iperf 3.1.3: Ø61.4 (57-63)
; iperf3 Client (transmit) TCP 1 m 4M x10; iperf 3.1.3: Ø55 (51-69)

Cameras - One more lens in the K51S

Recording front camera
Recording front camera

Four camera modules are found in the K51S, compared to the predecessor K50S a macro lens has been added, but only with a very low 2 megapixel resolution. The wide angle lens still has 5 megapixels, the main camera now has a much higher resolution, namely 32 megapixels and recently also pixel binning, which is called Quad-Cell at LG. This means that four pixels are combined to one pixel on the finished image. This reduces the resolution to 8 megapixels, but increases the light sensitivity of the individual pixels. If desired, the full resolution can also be used.

Since macro lens is only used in the special macro mode, there is at least a multi-level zoom between wide angle and standard lens. The photos of the main camera look a bit pale in color, but are reasonably sharpened in detail, at least in the center of the picture. Sometimes, you can see clear pixel artifacts at the edges of the lens. With the wide angle lens, the sharpness in detail suffers, but the pictures are basically usable.

Videos can be recorded with a maximum of 1080p and 30 fps, you have to choose between a standard or a wide angle lens before recording. The brightness adjustment operates visibly graded, the compression of the videos also causes partly visible pixel artifacts during brightness transitions. The sharpness and brightness of the videos are, however, basically on a decent level.

The front camera with 13 megapixels has the same high resolution as its predecessor, it still makes acceptable selfies for the price range, but lacks sharpness of detail.

Image Comparison

Choose a scene and navigate within the first image. One click changes the position on touchscreens. One click on the zoomed-in image opens the original in a new window. The first image shows the scaled photograph of the test device.

Main Lens FlowerMain Lens EnvironmentMain Lens Low LightUltra wide angle
click to load images
ColorChecker
26.6 ∆E
46.6 ∆E
36.2 ∆E
32.9 ∆E
40.4 ∆E
54.6 ∆E
46 ∆E
32.6 ∆E
32.9 ∆E
24.1 ∆E
55.5 ∆E
56.7 ∆E
30.5 ∆E
41.3 ∆E
27.3 ∆E
63.1 ∆E
35.1 ∆E
39.6 ∆E
58.5 ∆E
59.9 ∆E
45.8 ∆E
33.8 ∆E
22.5 ∆E
12.8 ∆E
ColorChecker LG K51S: 39.8 ∆E min: 12.79 - max: 63.1 ∆E
ColorChecker
11.9 ∆E
9.7 ∆E
14.4 ∆E
15.6 ∆E
13.6 ∆E
9.7 ∆E
6.9 ∆E
13.1 ∆E
8.1 ∆E
8.9 ∆E
9.5 ∆E
7.4 ∆E
9.1 ∆E
11.3 ∆E
7.8 ∆E
3.5 ∆E
8.2 ∆E
13.3 ∆E
2.2 ∆E
4.7 ∆E
9.8 ∆E
10.3 ∆E
4.5 ∆E
1.4 ∆E
ColorChecker LG K51S: 8.96 ∆E min: 1.4 - max: 15.61 ∆E

Display - LG phone with IPS display

Sub-pixel Array
Sub-pixel Array

Full-HD resolution in a smartphone for just under 200 euros manufacturer's price is actually no longer too much to ask. The LG K51S nevertheless relies on a lower resolution 720p IPS display. This puts it at a clear disadvantage compared to, for example, the Samsung Galaxy M21, which with its AMOLED display can not only be much brighter if necessary, but also offers better black levels and better color representation.

To be fair, however, it must also be said that the LG K51S display does not do its job so badly for an IPS display: the deviations in color representation are better than with the predecessor and the black level is acceptable. However, an average luminosity of 393 cd/m² is not enough even for an inexpensive mid-range smartphone in 2020.

A great advantage for sensitive people: There is no PWM flickering.

395
cd/m²
405
cd/m²
386
cd/m²
394
cd/m²
407
cd/m²
385
cd/m²
393
cd/m²
390
cd/m²
386
cd/m²
Distribution of brightness
X-Rite i1Pro 2
Maximum: 407 cd/m² Average: 393.4 cd/m² Minimum: 2.58 cd/m²
Brightness Distribution: 95 %
Center on Battery: 407 cd/m²
Contrast: 768:1 (Black: 0.53 cd/m²)
ΔE Color 4.17 | 0.6-29.43 Ø5.7
ΔE Greyscale 3.8 | 0.64-98 Ø5.9
94.7% sRGB (Calman 2D)
Gamma: 2.235
LG K51S
IPS, 1600x720, 6.55
LG K50S
IPS, 1560x720, 6.50
Samsung Galaxy M21
Super AMOLED, 2340x1080, 6.40
Honor 9X Lite
IPS, 2340x1080, 6.50
Response Times
-12%
74%
25%
Response Time Grey 50% / Grey 80% *
42 (23, 19)
52 (21, 31)
-24%
10 (5, 5)
76%
36 (17, 19)
14%
Response Time Black / White *
28 (15, 13)
28 (13, 15)
-0%
8 (5, 3)
71%
18 (7, 11)
36%
PWM Frequency
100 (10)
215.5
Screen
-1%
41%
-1%
Brightness middle
407
486
19%
617
52%
435
7%
Brightness
393
464
18%
614
56%
422
7%
Brightness Distribution
95
90
-5%
95
0%
93
-2%
Black Level *
0.53
0.33
38%
0.77
-45%
Contrast
768
1473
92%
565
-26%
Colorchecker DeltaE2000 *
4.17
5.79
-39%
2.11
49%
3.31
21%
Colorchecker DeltaE2000 max. *
8.28
11.87
-43%
3.41
59%
6.8
18%
Greyscale DeltaE2000 *
3.8
7.1
-87%
2.6
32%
3.2
16%
Gamma
2.235 98%
2.283 96%
2.073 106%
2.3 96%
CCT
7227 90%
8511 76%
6921 94%
6894 94%
Total Average (Program / Settings)
-7% / -3%
58% / 49%
12% / 5%

* ... smaller is better

Display Response Times

Display response times show how fast the screen is able to change from one color to the next. Slow response times can lead to afterimages and can cause moving objects to appear blurry (ghosting). Gamers of fast-paced 3D titles should pay special attention to fast response times.
       Response Time Black to White
28 ms ... rise ↗ and fall ↘ combined↗ 15 ms rise
↘ 13 ms fall
The screen shows relatively slow response rates in our tests and may be too slow for gamers.
In comparison, all tested devices range from 0.8 (minimum) to 240 (maximum) ms. » 60 % of all devices are better.
This means that the measured response time is worse than the average of all tested devices (24.3 ms).
       Response Time 50% Grey to 80% Grey
42 ms ... rise ↗ and fall ↘ combined↗ 23 ms rise
↘ 19 ms fall
The screen shows slow response rates in our tests and will be unsatisfactory for gamers.
In comparison, all tested devices range from 0.8 (minimum) to 636 (maximum) ms. » 55 % of all devices are better.
This means that the measured response time is similar to the average of all tested devices (38.6 ms).

Screen Flickering / PWM (Pulse-Width Modulation)

To dim the screen, some notebooks will simply cycle the backlight on and off in rapid succession - a method called Pulse Width Modulation (PWM) . This cycling frequency should ideally be undetectable to the human eye. If said frequency is too low, users with sensitive eyes may experience strain or headaches or even notice the flickering altogether.
Screen flickering / PWM not detected

In comparison: 51 % of all tested devices do not use PWM to dim the display. If PWM was detected, an average of 9661 (minimum: 5 - maximum: 142900) Hz was measured.


CalMAN Grayscale
CalMAN Grayscale
CalMAN Color accuracy
CalMAN Color accuracy
CalMAN Color space
CalMAN Color space
CalMAN Saturation
CalMAN Saturation

Performance, emissions and battery life - More power desirable

The LG K51S is equipped with a MediaTek Helio P35, which offers rather low performance compared to similarly expensive smartphones. Compared to its predecessor, it is after all a significant performance upgrade. For more complex apps, the smartphone is less suitable, but navigating through the menu is usually smooth.

The microSD reader does its job at a normal speed level, as we noticed in the test with the Toshiba Exceria Pro M501 reference card. In terms of internal memory, however, there are now significantly faster smartphones at this price level.

The warming under load is negligible and will hardly make itself unpleasantly noticeable even in hot environments.

The loudspeaker shows a rather similar sound image to its predecessor, i.e. strongly emphasized trebles, which make the sound seem less voluminous. However, voices are reproduced properly. The connection of external audio devices via 3.5mm connector or Bluetooth is no problem and delivers clean sound.

Unfortunately, our test device can't reach the runtimes of its predecessor in the WLAN test with fixed screen brightness. 13:23 hours is decent, but there are significantly more enduring smartphones at this price level. The charger has at least become a bit more powerful and now only needs about 2:30 hours for a full battery charge, but it's still far from a quick charge level.

Geekbench 5.1 - 5.3
64 Bit Multi-Core Score (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
539 Points ∼27%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1322 Points ∼67% +145%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
1320 Points ∼67% +145%
Average Mediatek Helio P35 MT6765
  (539 - 967, n=3)
803 Points ∼41% +49%
Average of class Smartphone
  (421 - 4160, n=149)
1968 Points ∼100% +265%
64 Bit Single-Core Score (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
150 Points ∼26%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
349 Points ∼61% +133%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
331 Points ∼58% +121%
Average Mediatek Helio P35 MT6765
  (150 - 173, n=3)
164 Points ∼29% +9%
Average of class Smartphone
  (124 - 1604, n=149)
571 Points ∼100% +281%
PCMark for Android
Work 2.0 performance score (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
4982 Points ∼72%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
3965 Points ∼58% -20%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
5892 Points ∼86% +18%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
6887 Points ∼100% +38%
Average Mediatek Helio P35 MT6765
  (3814 - 5794, n=9)
5008 Points ∼73% +1%
Average of class Smartphone
  (2630 - 15299, n=549)
6067 Points ∼88% +22%
Work performance score (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
5810 Points ∼62%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
4526 Points ∼49% -22%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
6043 Points ∼65% +4%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
9322 Points ∼100% +60%
Average Mediatek Helio P35 MT6765
  (4040 - 7753, n=7)
5938 Points ∼64% +2%
Average of class Smartphone
  (1077 - 19989, n=703)
6654 Points ∼71% +15%
3DMark
2560x1440 Sling Shot Extreme (ES 3.1) Unlimited Physics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
971 Points ∼39%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
927 Points ∼37% -5%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
2260 Points ∼91% +133%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
2479 Points ∼100% +155%
Average Mediatek Helio P35 MT6765
  (766 - 1221, n=9)
1093 Points ∼44% +13%
Average of class Smartphone
  (573 - 5780, n=556)
2277 Points ∼92% +135%
2560x1440 Sling Shot Extreme (ES 3.1) Unlimited Graphics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
464 Points ∼20%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
434 Points ∼19% -6%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1532 Points ∼67% +230%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
847 Points ∼37% +83%
Average Mediatek Helio P35 MT6765
  (432 - 489, n=9)
464 Points ∼20% 0%
Average of class Smartphone
  (75 - 12146, n=556)
2276 Points ∼100% +391%
2560x1440 Sling Shot Extreme (ES 3.1) Unlimited (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
525 Points ∼25%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
492 Points ∼23% -6%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1650 Points ∼78% +214%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
992 Points ∼47% +89%
Average Mediatek Helio P35 MT6765
  (496 - 564, n=9)
531 Points ∼25% +1%
Average of class Smartphone
  (93 - 9643, n=557)
2103 Points ∼100% +301%
2560x1440 Sling Shot OpenGL ES 3.0 Unlimited Physics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
927 Points ∼38%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
902 Points ∼37% -3%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1917 Points ∼78% +107%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
2456 Points ∼100% +165%
Average Mediatek Helio P35 MT6765
  (653 - 1213, n=9)
1063 Points ∼43% +15%
Average of class Smartphone
  (375 - 5765, n=588)
2192 Points ∼89% +136%
2560x1440 Sling Shot OpenGL ES 3.0 Unlimited Graphics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
744 Points ∼24%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
701 Points ∼23% -6%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1601 Points ∼52% +115%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
1369 Points ∼44% +84%
Average Mediatek Helio P35 MT6765
  (695 - 817, n=9)
757 Points ∼24% +2%
Average of class Smartphone
  (70 - 22052, n=588)
3102 Points ∼100% +317%
2560x1440 Sling Shot OpenGL ES 3.0 Unlimited (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
778 Points ∼30%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
738 Points ∼29% -5%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1662 Points ∼65% +114%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
1518 Points ∼59% +95%
Average Mediatek Helio P35 MT6765
  (725 - 881, n=9)
806 Points ∼32% +4%
Average of class Smartphone
  (88 - 11895, n=588)
2553 Points ∼100% +228%
2560x1440 Sling Shot Extreme (ES 3.1) Physics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
907 Points ∼37%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
872 Points ∼35% -4%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
2186 Points ∼89% +141%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
2459 Points ∼100% +171%
Average Mediatek Helio P35 MT6765
  (435 - 1183, n=9)
978 Points ∼40% +8%
Average of class Smartphone
  (435 - 5318, n=636)
2149 Points ∼87% +137%
2560x1440 Sling Shot Extreme (ES 3.1) Graphics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
145 Points ∼8%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
267 Points ∼14% +84%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1445 Points ∼76% +897%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
857 Points ∼45% +491%
Average Mediatek Helio P35 MT6765
  (145 - 508, n=9)
350 Points ∼18% +141%
Average of class Smartphone
  (53 - 11573, n=636)
1897 Points ∼100% +1208%
2560x1440 Sling Shot Extreme (ES 3.1) (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
178 Points ∼10%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
316 Points ∼18% +78%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
1563 Points ∼87% +778%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
1002 Points ∼56% +463%
Average Mediatek Helio P35 MT6765
  (178 - 512, n=9)
378 Points ∼21% +112%
Average of class Smartphone
  (68 - 9138, n=637)
1798 Points ∼100% +910%
2560x1440 Sling Shot OpenGL ES 3.0 Physics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
959 Points ∼39%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
900 Points ∼37% -6%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
2176 Points ∼90% +127%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
2429 Points ∼100% +153%
Average Mediatek Helio P35 MT6765
  (722 - 1177, n=9)
1047 Points ∼43% +9%
Average of class Smartphone
  (293 - 5301, n=678)
2020 Points ∼83% +111%
2560x1440 Sling Shot OpenGL ES 3.0 Graphics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
214 Points ∼9%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
449 Points ∼18% +110%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
2092 Points ∼83% +878%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
1355 Points ∼54% +533%
Average Mediatek Helio P35 MT6765
  (205 - 736, n=9)
523 Points ∼21% +144%
Average of class Smartphone
  (43 - 16670, n=677)
2517 Points ∼100% +1076%
2560x1440 Sling Shot OpenGL ES 3.0 (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
259 Points ∼12%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
505 Points ∼23% +95%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
2110 Points ∼98% +715%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
1503 Points ∼70% +480%
Average Mediatek Helio P35 MT6765
  (244 - 802, n=9)
583 Points ∼27% +125%
Average of class Smartphone
  (55 - 11256, n=680)
2149 Points ∼100% +730%
1280x720 offscreen Ice Storm Unlimited Physics (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
12136 Points ∼56%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
10404 Points ∼48% -14%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
19902 Points ∼92% +64%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
21625 Points ∼100% +78%
Average Mediatek Helio P35 MT6765
  (10689 - 17468, n=7)
15446 Points ∼71% +27%
Average of class Smartphone
  (735 - 59268, n=822)
15848 Points ∼73% +31%
1280x720 offscreen Ice Storm Unlimited Graphics Score (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
11417 Points ∼40%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
10777 Points ∼38% -6%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
25024 Points ∼87% +119%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
21470 Points ∼75% +88%
Average Mediatek Helio P35 MT6765
  (7061 - 12205, n=7)
10938 Points ∼38% -4%
Average of class Smartphone
  (536 - 224130, n=820)
28686 Points ∼100% +151%
1280x720 offscreen Ice Storm Unlimited Score (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
11569 Points ∼49%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
10692 Points ∼45% -8%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
23670 Points ∼100% +105%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
21504 Points ∼91% +86%
Average Mediatek Helio P35 MT6765
  (7637 - 13081, n=7)
11674 Points ∼49% +1%
Average of class Smartphone
  (662 - 117606, n=820)
21995 Points ∼93% +90%
GFXBench
Aztec Ruins High Tier Onscreen (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
4.4 fps ∼37%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
4.2 fps ∼36% -5%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
5.6 fps ∼47% +27%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
4.2 fps ∼36% -5%
Average Mediatek Helio P35 MT6765
  (2.2 - 4.7, n=8)
3.63 fps ∼31% -17%
Average of class Smartphone
  (0.61 - 60, n=348)
11.8 fps ∼100% +168%
2560x1440 Aztec Ruins High Tier Offscreen (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
1.4 fps ∼17%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
1.4 fps ∼17% 0%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
3.5 fps ∼42% +150%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
2.6 fps ∼31% +86%
Average Mediatek Helio P35 MT6765
  (1.4 - 1.5, n=8)
1.438 fps ∼17% +3%
Average of class Smartphone
  (0.21 - 101, n=346)
8.28 fps ∼100% +491%
Aztec Ruins Normal Tier Onscreen (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
6.9 fps ∼39%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
6.7 fps ∼38% -3%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
9.2 fps ∼53% +33%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
6.4 fps ∼37% -7%
Average Mediatek Helio P35 MT6765
  (3.5 - 7.4, n=9)
5.86 fps ∼33% -15%
Average of class Smartphone
  (1.4 - 60, n=352)
17.5 fps ∼100% +154%
1920x1080 Aztec Ruins Normal Tier Offscreen (sort by value)
LG K51S
Mediatek Helio P35 MT6765, PowerVR GE8320, 3072
3.9 fps ∼19%
LG K50S
Mediatek Helio P22 MT6762, PowerVR GE8320, 3072
3.7 fps ∼18% -5%
Samsung Galaxy M21
Samsung Exynos 9611, Mali-G72 MP3, 4096
10 fps ∼50% +156%
Honor 9X Lite
HiSilicon Kirin 710, Mali-G51 MP4, 4096
7 fps ∼35% +79%
Average Mediatek Helio P35 MT6765
  (3.8 - 3.9, n=9)
3.84 fps ∼19% -2%
Average of class Smartphone
  (0.6 - 257, n=351)
20.2 fps ∼100% +418%
LG K51SLG K50SSamsung Galaxy M21Honor 9X LiteAverage 64 GB eMMC FlashAverage of class Smartphone
AndroBench 3-5
-10%
130%
51%
8%
17%
Sequential Write 256KB SDCard
59.3 (Toshiba Exceria Pro M501)
58 (Tohsiba Exceria Pro M501)
-2%
62.2 (Toshiba Exceria Pro M501)
5%
69.2 (Toshiba Exceria Pro M501)
17%
58 (11.2 - 74.7, n=131)
-2%
51.4 (1.7 - 87.1, n=550)
-13%
Sequential Read 256KB SDCard
79.6 (Toshiba Exceria Pro M501)
78.3 (Tohsiba Exceria Pro M501)
-2%
77.9 (Toshiba Exceria Pro M501)
-2%
76 (Toshiba Exceria Pro M501)
-5%
77.1 (21.1 - 87.2, n=131)
-3%
69.3 (8.1 - 96.5, n=550)
-13%
Random Write 4KB
18.8
18.6
-1%
124.2
561%
72.4
285%
28.1 (3.4 - 147, n=150)
49%
39 (0.14 - 319, n=916)
107%
Random Read 4KB
58.9
54.3
-8%
126
114%
44.8
-24%
56.5 (11.4 - 149, n=150)
-4%
62.1 (1.59 - 325, n=916)
5%
Sequential Write 256KB
165.2
86.6
-48%
192.7
17%
200.9
22%
176 (40 - 254, n=150)
7%
136 (2.99 - 1321, n=916)
-18%
Sequential Read 256KB
266.1
272.8
3%
487.8
83%
286.8
8%
273 (95.6 - 704, n=150)
3%
358 (12.1 - 2037, n=916)
35%

Temperature

Max. Load
 36.1 °C
97 F
34.6 °C
94 F
32.5 °C
91 F
 
 37.8 °C
100 F
34.4 °C
94 F
32.6 °C
91 F
 
 38.3 °C
101 F
35 °C
95 F
32.5 °C
91 F
 
Maximum: 38.3 °C = 101 F
Average: 34.9 °C = 95 F
32.6 °C
91 F
35.4 °C
96 F
36.9 °C
98 F
32.6 °C
91 F
36.2 °C
97 F
38.1 °C
101 F
33.6 °C
92 F
36.6 °C
98 F
37.8 °C
100 F
Maximum: 38.1 °C = 101 F
Average: 35.5 °C = 96 F
Power Supply (max.)  39.8 °C = 104 F | Room Temperature 21.5 °C = 71 F | Fluke t3000FC (calibrated), Voltcraft IR-260
(±) The average temperature for the upper side under maximal load is 34.9 °C / 95 F, compared to the average of 32.9 °C / 91 F for the devices in the class Smartphone.
(+) The maximum temperature on the upper side is 38.3 °C / 101 F, compared to the average of 35.3 °C / 96 F, ranging from 22.4 to 51.7 °C for the class Smartphone.
(+) The bottom heats up to a maximum of 38.1 °C / 101 F, compared to the average of 33.9 °C / 93 F
(+) In idle usage, the average temperature for the upper side is 27.4 °C / 81 F, compared to the device average of 32.9 °C / 91 F.


Heatmap Front
Heatmap Front
Heatmap Back side
Heatmap Back side

Speakers

dB(A) 0102030405060708090Deep BassMiddle BassHigh BassLower RangeMidsHigher MidsLower HighsMid HighsUpper HighsSuper Highs2038.942.52536.838.23133.131.54032.936.55035.3396328.726.98019.121.910020.420.412520.52716017.224.920014.229.925014.538.231514.545.140012.852.350013.459.663013.664.780018.968.5100018.670125021.265.5160014.968200014.167.5250014.665.7315014.768.8400015.572.1500016.266.36300176780001871.41000018.873.21250019.657.51600020.554.1SPL58.42980.5N10.61.147.9median 16.2median 65.5Delta2.51242.943.842.341.434.836.73939.940.838.434.433.628.128.225.12523.624.622.125.720.232.819.638.318.447.518.953.620.157.72062.617.563.516.171.515.57317.8711672.415.972.516.170.616.364.416.565.516.566.316.967.316.662.21752.316.548.366.429.381.418.51.246.7median 17median 62.61.711.3hearing rangehide median Pink NoiseLG K51SLG K50S
Frequency diagram (checkboxes can be checked and unchecked to compare devices)
LG K51S audio analysis

(±) | speaker loudness is average but good (80.5 dB)
Bass 100 - 315 Hz
(-) | nearly no bass - on average 34.6% lower than median
(±) | linearity of bass is average (10.2% delta to prev. frequency)
Mids 400 - 2000 Hz
(+) | balanced mids - only 4% away from median
(±) | linearity of mids is average (8.2% delta to prev. frequency)
Highs 2 - 16 kHz
(+) | balanced highs - only 3.7% away from median
(+) | highs are linear (6.1% delta to prev. frequency)
Overall 100 - 16.000 Hz
(±) | linearity of overall sound is average (25.1% difference to median)
Compared to same class
» 59% of all tested devices in this class were better, 11% similar, 30% worse
» The best had a delta of 13%, average was 24%, worst was 65%
Compared to all devices tested
» 75% of all tested devices were better, 6% similar, 20% worse
» The best had a delta of 3%, average was 21%, worst was 65%

LG K50S audio analysis

(±) | speaker loudness is average but good (81.4 dB)
Bass 100 - 315 Hz
(-) | nearly no bass - on average 30.2% lower than median
(±) | linearity of bass is average (9.7% delta to prev. frequency)
Mids 400 - 2000 Hz
(±) | higher mids - on average 6.6% higher than median
(±) | linearity of mids is average (8% delta to prev. frequency)
Highs 2 - 16 kHz
(+) | balanced highs - only 4.5% away from median
(+) | highs are linear (5.1% delta to prev. frequency)
Overall 100 - 16.000 Hz
(±) | linearity of overall sound is average (27.7% difference to median)
Compared to same class
» 74% of all tested devices in this class were better, 9% similar, 17% worse
» The best had a delta of 13%, average was 24%, worst was 65%
Compared to all devices tested
» 83% of all tested devices were better, 5% similar, 12% worse
» The best had a delta of 3%, average was 21%, worst was 65%

Battery life

LG K51S
4000 mAh
LG K50S
4000 mAh
Samsung Galaxy M21
6000 mAh
Honor 9X Lite
3750 mAh
Average of class Smartphone
 
Battery Runtime
WiFi Websurfing 1.3
803
946
18%
1298
62%
793
-1%
706 (223 - 2636, n=783)
-12%
Battery Runtime
NBC WiFi Websurfing Battery Test 1.3
13h 23min

Pros

+ stable case
+ hardly any heating
+ NFC
+ flexible cameras

Cons

- slow WLAN
- dark screen
- comparatively weak power

Verdict – Seems unfortunately antiquated

In Review: LG K51S.
In Review: LG K51S.

The LG K51S lags a generation behind similarly priced smartphones from 2020, not only in terms of software. Also in terms of performance, battery life, WLAN speed and screen brightness, people are now more used to getting more value for their money. The slow memory is another negative aspect.

But there are also positive things like the low temperature development, the stable case, which according to the manufacturer even underwent some stability tests according to MIL-STD-810G, or the at least solid sounding loudspeaker.

The LG K51S unfortunately falls behind the competition, but at least it can offer a flexible camera and a stable housing with an individually designed photo module.

In terms of flexibility and image quality, the camera is at least on a similar level to the competition, and with NFC there is the most important communication interface for mobile payment.

But the impression remains that there are simply better offers than the LG K51S. Although LG has praised the improvement in the frequency of software updates, there is unfortunately little evidence of this at present.

LG K51S - 09/25/2020 v7
Florian Schmitt

Chassis
80%
Keyboard
65 / 75 → 87%
Pointing Device
87%
Connectivity
38 / 70 → 54%
Weight
88%
Battery
90%
Display
84%
Games Performance
7 / 64 → 11%
Application Performance
53 / 86 → 62%
Temperature
91%
Noise
100%
Audio
75 / 90 → 83%
Camera
58%
Average
71%
76%
Smartphone - Weighted Average

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> Notebook / Laptop Reviews and News > Reviews > LG K51S Smartphone Review – Too little, too late?
Florian Schmitt, 2020-09-25 (Update: 2020-09-25)
Florian Schmitt
Editor of the original article: Florian Schmitt - Managing Editor Mobile
When I was 12, the first computer came into the house and immediately I started tinkering around, taking it apart, getting new parts and replacing them - after all, there always had to be enough power for the current games. When I came to Notebookcheck in 2009, I was passionate about testing gaming notebooks. Since 2012, my attention has been focused on smartphones, tablets and future technologies.