Products
LG B4 OLED
TCL QM851G
Tested using Methodology v2.0.1
Updated Sep 10, 2025 06:38 PM
SEE PRICE
BestBuy.com
Tested using Methodology v2.0.1
Updated Aug 12, 2025 01:39 PM
SEE PRICE
BestBuy.com
Resolution4k
Native Refresh Rate
120Hz
TypeOLED
Sub-Type
WOLED
Dolby Vision
Yes
Screen Finish
Glossy
Resolution4k
Native Refresh Rate
144Hz
TypeLED
Sub-Type
VA
Dolby Vision
Yes
Screen Finish
Glossy
Our Verdict
LG B4 OLED
TCL QM851G
The LG B4 OLED and TCL QM851G are closely matched, each with its own clear strengths and weaknesses. The LG is a powerhouse in dark rooms thanks to its nearly perfect black levels; the TCL is no slouch when it comes to contrast, but it can't match an OLED. It's also a spectacular gaming TV with nearly instantaneous pixel transitions; the TCL supports higher refresh rates, but that doesn't quite offset the LG's sheer responsiveness. Still, the TCL has a significant edge in HDR and SDR brightness and in HDR color volume, making it look far more vibrant—especially in brighter rooms, where the LG can look a bit dim.
Variants
- OLED48B4AUA (48")
- OLED55B4AUA (55")
- OLED65B4AUA (65")
- OLED77B4AUA (77")
- OLED83B4AUA (83")
- 65QM851G (65")
- 75QM851G (75")
- 85QM851G (85")
- 98QM851G (98")
Check Price
48"
OLED48B4AUA
SEARCH
Amazon.com
48"
55"
OLED55B4AUA
SEE PRICE
BestBuy.com
55"
65"
OLED65B4AUA
SEE PRICE
BestBuy.com
65"
65QM851G
SEE PRICE
Amazon.com
75"
75"
75QM851G
SEE PRICE
Amazon.com
77"
OLED77B4AUA
SEE PRICE
BestBuy.com
77"
83"
OLED83B4AUA
SEE PRICE
LG.com
83"
85"
85"
85QM851G
SEE PRICE
BestBuy.com
98"
98"
98QM851G
SEARCH
Amazon.com
Main Differences for
Mixed Usage
Mixed Usage
Threshold
Mixed Usage
8.1
8.2
HDR Brightness
6.9
9.4
SDR Brightness
6.6
9.5
Contrast
10
8.9
Full Comparison
Brightness
HDR Brightness
6.9
9.4
HDR Hallway Photo
HDR Cityscape Photo
HDR Landscape Photo
Hallway Lights (~1950 cd/m²)
647 cd/m²
1,472 cd/m²
Yellow Skyscraper (~700 cd/m²)
467 cd/m²
611 cd/m²
Landscape Pool (~300 cd/m²)
258 cd/m²
473 cd/m²
Peak 2% Window
685 cd/m²
2,564 cd/m²
Peak 10% Window
675 cd/m²
3,467 cd/m²
Peak 25% Window
509 cd/m²
3,338 cd/m²
Peak 50% Window
328 cd/m²
1,814 cd/m²
Peak 100% Window
147 cd/m²
967 cd/m²
Sustained 2% Window
678 cd/m²
2,497 cd/m²
Sustained 10% Window
666 cd/m²
3,319 cd/m²
Sustained 25% Window
501 cd/m²
3,253 cd/m²
Sustained 50% Window
326 cd/m²
1,810 cd/m²
Sustained 100% Window
144 cd/m²
965 cd/m²
Automatic Brightness Limiting (ABL)
0.094
0.060
HDR Brightness In Game Mode
6.8
9.4
HDR Hallway Photo
HDR Cityscape Photo
HDR Landscape Photo
Hallway Lights (~1950 cd/m²)
631 cd/m²
1,393 cd/m²
Yellow Skyscraper (~700 cd/m²)
407 cd/m²
625 cd/m²
Landscape Pool (~300 cd/m²)
278 cd/m²
447 cd/m²
Peak 2% Window
663 cd/m²
4,167 cd/m²
Peak 10% Window
665 cd/m²
3,425 cd/m²
Peak 25% Window
503 cd/m²
3,366 cd/m²
Peak 50% Window
326 cd/m²
1,796 cd/m²
Peak 100% Window
147 cd/m²
956 cd/m²
Sustained 2% Window
656 cd/m²
2,384 cd/m²
Sustained 10% Window
657 cd/m²
3,300 cd/m²
Sustained 25% Window
497 cd/m²
3,251 cd/m²
Sustained 50% Window
326 cd/m²
1,792 cd/m²
Sustained 100% Window
144 cd/m²
953 cd/m²
Automatic Brightness Limiting (ABL)
0.093
0.060
SDR Brightness
6.6
9.5
Real Scene Peak Brightness
398 cd/m²
1,108 cd/m²
Peak 2% Window
425 cd/m²
4,043 cd/m²
Peak 10% Window
433 cd/m²
3,355 cd/m²
Peak 25% Window
426 cd/m²
3,291 cd/m²
Peak 50% Window
418 cd/m²
1,767 cd/m²
Peak 100% Window
244 cd/m²
940 cd/m²
Sustained 2% Window
419 cd/m²
2,320 cd/m²
Sustained 10% Window
429 cd/m²
3,238 cd/m²
Sustained 25% Window
423 cd/m²
3,171 cd/m²
Sustained 50% Window
416 cd/m²
1,761 cd/m²
Sustained 100% Window
242 cd/m²
938 cd/m²
Automatic Brightness Limiting (ABL)
0.037
0.060
Black Level
Contrast
10
8.9
Contrast Picture
Contrast
Inf : 1
201,150 : 1
Native Contrast
Inf : 1
6,515 : 1
Lighting Zone Precision
10
8.5
Lighting Zone Precision Picture
Lighting Zone Transitions
10
8.5
Preferred LD Video, Moving Object
Local Dimming
No
Yes
Backlight
No Backlight
Full-Array
Dimming Zone Count Of The Tested TV
8,294,400
2,880
Contrast And Dark Details In Game Mode
9.5
9.0
Lighting Zone Precision Photo In Game Mode
Preferred LD Video, Moving Object In Game Mode
Game Transitions With VRR And Preferred LD
Black Uniformity
10
8.9
Black Uniformity Picture With Preferred Local Dimming
Std. Dev.
N/A
0.154%
Native Black Uniformity Picture
Native Std. Dev.
0.209%
0.569%
Color
SDR Color Volume
7.9
7.7
DCI-P3 Gamut Rings
CIELAB DCI-P3 Coverage
94.07%
90.94%
BT.2020 Gamut Rings
CIELAB BT.2020 Coverage
63.23%
67.01%
HDR Color Volume
7.4
9.0
P3 Color Volume ITP Picture
1,000 cd/m² DCI P3 Coverage ITP
66.9%
85.2%
2020 Color Volume ITP Picture
10,000 cd/m² BT.2020 Coverage ITP
34.2%
54.8%
White Luminance
719 cd/m²
2,513 cd/m²
Red Luminance
89 cd/m²
585 cd/m²
Green Luminance
306 cd/m²
1,885 cd/m²
Blue Luminance
38 cd/m²
189 cd/m²
Cyan Luminance
334 cd/m²
2,075 cd/m²
Magenta Luminance
115 cd/m²
773 cd/m²
Yellow Luminance
366 cd/m²
2,451 cd/m²
SDR Pre-Calibration Color Accuracy
9.2
7.5
Pre White Balance Picture
Pre Gamma Curve Picture
Pre Color Picture
White Balance dE 2000
1.30
3.36
Color dE 2000
1.20
2.07
Gamma
2.13
2.09
Color Temperature
6,550 K
6,127 K
Picture Mode
Expert (Dark Space)
Movie
Color Temp Setting
Warm 50
Warm -5
Gamma Setting
2.2
2.2
SDR Post-Calibration Color Accuracy
9.6
9.6
Post White Balance Picture
Post Gamma Curve Picture
Post Color Picture
White Balance dE 2000
0.22
0.24
Color dE 2000
1.03
0.82
Gamma
2.20
2.20
Color Temperature
6,495 K
6,483 K
White Balance Calibration
22 point
20 point
Color Calibration
Yes
Yes
HDR Pre-Calibration Color Accuracy
9.3
5.7
HDR Pre White Balance Picture
HDR Pre Color Picture
White Balance dE ITP
2.70
41.45
Color dE ITP
5.4
49.6
Color Temperature
6,587 K
6,308 K
Picture Mode
Cinema
Movie
HDR Post-Calibration Color Accuracy
9.4
7.0
HDR Post White Balance Picture
HDR Post Color Picture
White Balance dE ITP
2.29
19.70
Color dE ITP
5.00
8.60
Color Temperature
6,558 K
6,276 K
Processing
PQ EOTF Tracking
9.6
3.9
PQ EOTF Graph
600 Nit Tracking Delta
0.0012
0.0313
1000 Nit Tracking Delta
0.0011
0.0314
4000 Nit Tracking Delta
0.0018
0.0314
Low-Quality Content Smoothing
7.7
8.1
Low-Quality Content Smoothing Picture
Smoothing
7.5
8.5
Detail Preservation
8.0
7.0
Upscaling: Sharpness Processing
8.0
7.5
Sharpness Picture - 480p
HDR Native Gradient
8.0
7.8
HDR Gradient Picture
100% Black To 50% Gray
6.0
6.0
50% Gray To 100% White
10
6.0
100% Black To 50% Red
8.0
8.0
50% Red To 100% Red
10
10
100% Black To 50% Green
6.0
8.0
50% Green To 100% Green
8.0
8.0
100% Black To 50% Blue
8.0
8.0
50% Blue To 100% Blue
8.0
8.0
Game Mode Responsiveness
Input Lag
8.8
8.4
1080p @ 60Hz
10.5 ms
14.1 ms
1080p @ 60Hz Outside Game Mode
155.9 ms
125.0 ms
1080p @ 120Hz
5.8 ms
6.1 ms
1080p @ Max Refresh Rate
5.8 ms
8.0 ms
4k @ 60Hz
10.6 ms
14.1 ms
4k @ 60Hz @ 4:4:4
10.6 ms
15.0 ms
4k @ 60Hz Outside Game Mode
139.2 ms
124.7 ms
4k @ 60Hz With Interpolation
130.6 ms
116.5 ms
4k @ 120Hz
5.5 ms
5.9 ms
4k @ Max Refresh Rate
5.5 ms
5.0 ms
8k @ 60Hz
N/A
N/A
Supported Resolutions
9.1
9.5
Resolution
4k
4k
480p @ 59.94Hz (Widescreen)
Yes
Yes
720p @ 59.94Hz
Yes
Yes
1080p @ 60Hz @ 4:4:4
Yes
Yes
1080p @ 120Hz
Yes
Yes
1080p Maximum Refresh Rate
120 Hz
240 Hz
4k @ 60Hz
Yes
Yes
4k @ 60Hz @ 4:4:4
Yes
Yes
4k @ 120Hz
Yes
Yes
4k @ 120Hz @ 4:4:4
Yes
Yes
4k Maximum Refresh Rate
120 Hz
144 Hz
8k @ 30Hz Or 24Hz
No
No
8k @ 60Hz
No
No
Variable Refresh Rate
7.5
8.8
Native Refresh Rate
120Hz
144Hz
Variable Refresh Rate
Yes
Yes
HDMI Forum VRR
Yes
Yes
FreeSync
Yes
Yes
G-SYNC Compatible
Yes (NVIDIA Certified)
Yes
4k VRR Maximum
120 Hz
144 Hz
4k VRR Minimum
< 20 Hz
< 20 Hz
1080p VRR Maximum
120 Hz
240 Hz
1080p VRR Minimum
< 20 Hz
< 20 Hz
VRR + Local Dimming
No Local Dimming
Yes
CAD In Game Mode @ Max Refresh Rate
9.7
7.5
Pursuit Photo Max Refresh
CAD Heatmap Max Refresh
Transition At Max Refresh
0 to 31
0 to 31
Avg. CAD
30
173
Best 10% CAD
7
71
Worst 10% CAD
90
303
CAD In Game Mode @ 120Hz
9.7
6.9
Pursuit Photo 120Hz
CAD Heatmap 120Hz
Transition At 120Hz
0 to 31
0 to 31
Avg. CAD
30
200
Best 10% CAD
7
69
Worst 10% CAD
90
482
CAD In Game Mode @ 60Hz
9.7
7.0
Pursuit Photo 60Hz
CAD Heatmap 60Hz
Transition 60Hz
0 to 31
0 to 31
Avg. CAD
37
217
Best 10% CAD
7
71
Worst 10% CAD
110
372
PS5 Compatibility
PS5 Screenshot
Auto Low Latency Mode (ALLM)
Yes
Yes
4k @ 120Hz
Yes
Yes
1440p @ 120Hz
Yes
Yes
1080p @ 120Hz
Yes
Yes
HDR
Yes
Yes
VRR
Yes
Yes
Xbox Series X|S Compatibility
Xbox Series X Screenshot
Auto Low Latency Mode (ALLM)
Yes
Yes
4k @ 120Hz
Yes
Yes
1440p @ 120Hz
Yes
Yes
1080p @ 120Hz
Yes
Yes
HDR
Yes
Yes
VRR
Yes
Yes
Motion Handling
Stutter
4.1
6.1
Frame Hold Time @ 24 fps
41.4 ms
36.2 ms
Frame Hold Time @ 60 fps
16.4 ms
11.2 ms
24p Judder
10
10
Judder-Free 24p
Yes
Yes
Judder-Free 24p via 60p
Yes
Yes
Judder-Free 24p via 60i
Yes
Yes
Judder-Free 24p via Native Apps
Yes
Yes
Response Time
9.6
8.1
Pursuit Photo 60Hz
Response Time Heatmap 60Hz
Transition At 60Hz
0 to 31
0 to 31
First Response Time
0.3 ms
5.5 ms
Total Response Time
2.9 ms
10.6 ms
Worst 10% Response Time
9.9 ms
22.9 ms
Flicker
Backlight chart
Flicker-Free
No
No
PWM Dimming Frequency
0 Hz
30,000 Hz
Black Frame Insertion (BFI)
BFI Picture
BFI Frequency Picture
Optional BFI
Yes
Yes
Min Flicker For 60 fps
60 Hz
60 Hz
60Hz For 60 fps
Yes
Yes
120Hz For 120 fps
No
Yes
Min Flicker For 60 fps In Game Mode
60 Hz
60 Hz
Motion Interpolation
Motion Interpolation (30 fps) Picture
Motion Interpolation (30 fps)
Yes
Yes
Motion Interpolation (60 fps) Picture
Motion Interpolation (60 fps)
Yes
Yes
Reflections
Direct Reflections
6.3
6.3
Ring Light Picture
Direct Reflections Graph
Peak Direct Reflection Intensity
46.9%
46.5%
Screen Finish
Glossy
Glossy
Ambient Black Level Raise
9.3
9.1
Black Level Raise Picture
Bright Room Black Level Raise Graph
Black Luminance @ 0 lx
0.00 cd/m²
0.00 cd/m²
Black Luminance @ 1000 lx
0.26 cd/m²
0.38 cd/m²
Total Reflected Light
8.3
7.8
Bright Room Off Picture
Ring Picture Total Reflection
Total Reflected Light Intensity
13,275% ⋅ pixel
12,962% ⋅ pixel
Diffraction Artifacts
No
Yes
Ambient Color Saturation
7.5
8.4
Bright Room Color Volume Graph
Low-Luminance Colors @ 1000 lx
66.31%
71.72%
Mid-Luminance Colors @ 1000 lx
60.54%
68.86%
High-Luminance Colors @ 1000 lx
44.08%
59.50%
Panel
Viewing Angle
9.0
6.2
Viewing Angle Video
Chroma Graph
Color Washout
52°
23°
Hue Graph
Color Shift
29°
31°
Lightness Graph
Brightness Loss
69°
30°
Black Level Raise
70°
18°
Gamma Shift
67°
18°
Gray Uniformity
8.2
7.1
50% Uniformity Picture
50% Std. Dev.
0.738%
2.225%
50% DSE
0.126%
0.170%
5% Uniformity Picture
5% Std. Dev.
0.470%
0.670%
5% DSE
0.100%
0.093%
Panel Technology
Spectral Power Distribution
Pixels Picture
Type
OLED
LED
Sub-Type
WOLED
VA
Subpixel Layout
RWBG
BGR
Inputs
Input Specifications
Side Inputs Picture
Rear Inputs Picture
HDMI
4 (4x HDMI 2.1)
4 (2x HDMI 2.0, 2x HDMI 2.1)
HDMI 2.1 Rated Speed
48 Gbps
48 Gbps
ATSC Tuner
1.0
3.0 (NEXTGEN TV)
USB Ports
2
3
USB 3.0
No
Yes (1)
Audio Out 3.5mm
0
1
Wi-Fi
Yes (2.4 GHz, 5 GHz)
Yes (2.4 GHz, 5 GHz)
Ethernet Speed
100 Mbps
100 Mbps
Composite In
0
1 (Adapter Required, Not Incl.)
Digital Optical Audio Out
1
1
Audio Passthrough
ARC/eARC Port
eARC
eARC
eARC: Dolby Atmos Over Dolby Digital Plus
Yes
Yes
eARC: Dolby Digital Plus 7.1
Yes
Yes
eARC: LPCM 7.1 Over Dolby MAT
Yes
Yes
eARC: Dolby TrueHD 7.1
Yes
Yes
eARC: DTS:X Over DTS-HD MA
Yes
Yes
eARC: DTS-HD Master Audio 7.1
Yes
Yes
eARC: LPCM Channels (Bitstream)
7.1
7.1
ARC: Dolby Digital 5.1
Yes
Yes
ARC: DTS 5.1
Yes
Yes
Optical: Dolby Digital 5.1
Yes
Yes
Optical: DTS 5.1
Yes
Yes
HDR Format Support
HDR10
Yes
Yes
HDR10+
No
Yes
Dolby Vision
Yes
Yes
HLG
Yes
Yes
Design
Style
Design Picture
Curved
No
No
Stand
Stand Picture
Back
Back Picture
Wall Mount
VESA 300x200
VESA 400x400
Borders
Borders Picture
Borders
0.39" (1.0 cm)
0.31" (0.8 cm)
Thickness
Thickness Picture
Max Thickness
1.81" (4.6 cm)
2.28" (5.8 cm)
Build Quality
8.5
8.5
Build quality picture
Smart Features
Interface
Smart TV Picture
Smart OS
webOS
Google TV
Version
24
12
Ad-Free
0.0
0.0
Ads Picture
Ads
Yes
Yes
Opt-out
No
No
Suggested Content in Home
No
Yes
Opt-out of Suggested Content
No
No
Remote
Remote Picture
Voice Control
Yes
Yes
TV Controls
Controls Picture
Mute Switch
No
Yes
In The Box
In The Box Picture
Misc
Power Consumption
72 W
66 W
Power Consumption (Max)
214 W
307 W
Firmware
03.10.37
V8-T653T02-LF1V085
Sound Quality
Frequency Response
7.0
7.0
Frequency Response
Low-Frequency Extension
84.76 Hz
75.51 Hz
Std. Dev. @ 70
3.82 dB
3.92 dB
Std. Dev. @ 80
3.81 dB
3.60 dB
Std. Dev. @ Max
5.99 dB
4.90 dB
Max
90.1 dB SPL
87.3 dB SPL
Dynamic Range Compression
3.31 dB
4.74 dB
Digital Room Correction
Yes
Yes
Check Price
48"
OLED48B4AUA
SEARCH
Amazon.com
48"
55"
OLED55B4AUA
SEE PRICE
BestBuy.com
55"
65"
OLED65B4AUA
SEE PRICE
BestBuy.com
65"
65QM851G
SEE PRICE
Amazon.com
75"
75"
75QM851G
SEE PRICE
Amazon.com
77"
OLED77B4AUA
SEE PRICE
BestBuy.com
77"
83"
OLED83B4AUA
SEE PRICE
LG.com
83"
85"
85"
85QM851G
SEE PRICE
BestBuy.com
98"
98"
98QM851G
SEARCH
Amazon.com
LG B4 OLED
TCL QM851G
Comments
LG B4 OLED vs TCL QM851G: Main Discussion
What do you think of these products? Let us know below.
Looking for a personalized buying advice from the RTINGS.com experts? Insiders have direct access to buying advice on our insider forum.