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    Table of Contents
  1. Intro
  2. Design
    1. Stand
    2. Borders
    3. Thickness
  3. Picture Quality
    1. Contrast
    2. Local Dimming
    3. SDR Peak Brightness
    4. Gray Uniformity
    5. Viewing Angle
    6. Black Uniformity
    7. Pre Calibration
    8. Post Calibration
    9. 480p Input
    10. 720p Input
    11. 1080p Input
    12. 4k Input
    13. Color Gamut
    14. Reflections
    15. 3D
    16. Pixels
  4. Motion
    1. Motion Blur
    2. Image Flicker
    3. 24p Playback
    4. Motion Interpolation
  5. Inputs
    1. Input Lag
    2. Supported Resolutions
    3. Side Inputs
    4. Rear Inputs
    5. Total Inputs
    6. Inputs Specifications
  6. Sound Quality
    1. Frequency Response
    2. Total Harmonic Distortion
  7. Smart Features
    1. Ads
    2. Remote
    3. Misc
  8. Conclusion
  9. Q&A
Reviewed on Dec 03, 2015

LG UF6400
TV REVIEW

Usage Ratings
6.6Mixed Usage
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What it is General purpose. The TV will be used for a variety of content and usages. Movies at night, TV shows during the day, video games from time to time, etc.
Score components:
6.1Movies
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What it is Movies in the dark. The TV will be used for watching movies in a controlled environment, directly in front, in a home theater way. Mostly only high quality content, like Blu-rays, UHD Blu-rays, streaming and a little bit of HDR.
Score components:
7.0TV Shows
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What it is TV Shows in a bright living room. The TV will be used in to watch TV shows, in a bright room during the day, from multiple viewing positions at different angles. The content watched has an average quality: cable, streaming, SD channels, etc.
Score components:
6.9Sports
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What it is Sports in a living room. The TV will be used to watch sports during the day, like football or hockey. Usually watched with a group, so from multiple viewing position.
Score components:
7.0Video Games
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What it is Video games. The TV will be used to play video games, directly in front, in a controlled light environment. Usually fast games, like online FPS, where motion blur and input lag is important.
Score components:
5.9HDR Movies
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What it is HDR Movies and TV shows. The TV will be used to watch 4k UHD HDR content, with a wide color gamut and a high peak brightness. Either via UHD Blu-rays or HDR streaming.
Score components:
4.3HDR Gaming
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What it is HDR Gaming. The TV will be used to play HDR video games using consoles that support it or on current generation gaming PCs. Xbox One S, PS4 Pro, GTX 10 series and AMD RX series graphics cards.
6.5PC Monitor
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What it is PC Monitor. The TV will be used as a PC monitor, from 2-3 feet away, either for productivity purposes or gaming. Sharp text is important, as well as a high resolution.
Score components:
Type : LED
Resolution : "4k"
Refresh Rate : 60 Hz

The LG UF6400 LED TV is the second 4k TV we have seen from LG which uses the less accurate RGBW pixel structure. Like most other IPS TVs, its picture quality isn't that great due to poor contrast ratio and black uniformity. Its wide viewing angle is its strong point, but unfortunately, this TV doesn't excel at anything.

Test Results
Design 6.5
Picture Quality 6.7
Motion 7.1
Inputs 6.2
Sound Quality 6.2
Smart Features 8.5
Pros
  • Good viewing angle
  • WebOS is a nice smart platform
Cons
  • Uses the less accurate RGBW 4k pixel structure
  • Poor picture quality in the dark
  • Does not excel at anything

Check Price

6.5

Design

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Score components: Subjectively assigned
LG UF6400 Design Picture
Curved : No

It isn't a TV that will turn heads, but it doesn't look bad, either. The stand is very sturdy, but it will require a table almost as wide as the TV.

Stand
LG UF6400 Stand Picture

Dimension of 49" TV stand: 28.6" by 8.2"

Borders
LG UF6400 Borders Picture
Borders : 0.74" (1.9 cm)

Thickness
LG UF6400 Thickness Picture
Max Thickness : 2.52" (6.4 cm)

6.7

Picture Quality

Because of its poor blacks and contrast, movies won't be great if you watch them in a dark room. With the lights on, this won't be as big of a problem. The TV is judder-free if you watch Blu-ray discs, which is great.

6.3 Contrast
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What it is: Brightness difference between white and black. This is the main component of picture quality.
When it matters: Always, but especially when watching dark scenes.
Score components:
Native Contrast
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What it is: Ratio of the white brightness divided by the blacks measured on our checkerboard test pattern with a white target of 100 cd/m².
When it matters: Dark scenes in a dark room.
Good value: > 3,000
Noticeable difference: 500
:
1181 : 1

This isn't the worst TV we have seen for blacks, but it is still near the bottom of the list. Blacks will look gray when you watch this TV in the dark.

0 Local Dimming
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What it is: The lights behind the LCD layer adapt to the picture displayed, improving the contrast ratio.
When it matters: Dark scenes viewed in a dark room.
Score components: Subjectively assigned
Local Dimming
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What it is: Whether it has a feature that controls the LEDs behind the LCD layer, to match the picture and darkens the dark portion of it.
When it matters: On LED TVs only. Dark scenes viewed in a dark room.
:
No
Backlight
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What it is: Configuration of the lights of the backlight.
When it matters: Effectiveness of the local dimming.
Good value: Full-array/direct lighting is better for local dimming. As for the uniformity of the screen, it depends on the implementation. Some edge-lit TVs have more uniform blacks than some full-array TVs.
:
Direct

5.9 SDR Peak Brightness
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What it is: How bright the screen can get. Measured with local dimming and with SDR content.
When it matters: Bright living rooms; bright objects; SDR content.
SDR Peak 2% Window
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What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 2% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright highlights, present on screen for a short time; especially for SDR content.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2
:
262 cd/m2
SDR Peak 100% Window
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What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 100% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2
:
262 cd/m2

6.2 Gray Uniformity
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What it is: Evenness of colors onscreen (not just gray).
When it matters: Solid colors. Sports, panning shots.
Score components:
LG UF6400 50% Uniformity Picture
50% Std. Dev.
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What it is: Average squared difference of pixels when displaying a mid 50% gray.
When it matters: Solid colors. Sports, panning shots.
Good value: < 2.5%
Noticeable difference: 1%
:
6.324 %
50% DSE
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What it is: High-frequency variance of uniformity. Dark spots on the screen.
When it matters: Solid colors. Sports, panning shots.
Good value: < 0.165%
Noticeable difference: 0.025%
:
0.201 %

There isn't much 'dirty screen effect' but the corners of the screen are very dark. This could be distracting while watching hockey, in particular.

6.2 Viewing Angle
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What it is: Color accuracy when viewed from the side.
When it matters: Large living rooms with multiple viewing positions.
Score components:
LCD Type
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What it is: Type of LCD technology used by the TV.
When it matters: Different technologies have different viewing angle properties.
Good value: IPS maintains good color accuracy at an angle, but has a poor contrast ratio from in front. VA has great picture quality in front, but loses saturation at an angle.
:
IPS
Color Shift
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What it is: Angle where the colors noticeable shift compared to when viewed from directly in front of the TV. 0 ° means directly facing the TV. Measurements are up to a maximum of 75 °.
When it matters: Large living rooms with multiple viewing positions.
Good value: > 50°
Noticeable difference: 10°
:
20 °
Brightness
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What it is: Angle where the brightness drops to 50% of the brightness directly in front of the TV. 0 ° means directly facing the TV. Measurements are up to a maximum of 75 °.
When it matters: Large living rooms with multiple viewing positions.
Good value: > 50°
Noticeable difference: 10°
:
30 °
Black Level
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What it is: Angle where the black level drops to 50% of the black level directly in front of the TV. 0 ° means directly facing the TV. Measurements are up to a maximum of 75 °.
When it matters: Large living rooms with multiple viewing positions.
Good value: > 50°
Noticeable difference: 10°
:
75 °

This is always the strong point of IPS TVs. The colors of the UF6400 don't lose much saturation when viewed from the side. This TV is suitable for a wide family room.

Update 01/06/2017: We have changed the methodology of testing. Since this is an old TV which we don't have anymore, we extrapolated the results from 2016 TVs.

6.7 Black Uniformity
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What it is: Evenness of blacks.
When it matters: Dark scenes viewed in a dark room.
Score components:
LG UF6400 Native Black Uniformity Picture
Native Std. Dev.
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What it is: Average of the squared difference of the blacks.
When it matters: Dark scenes viewed in a dark room.
Good value: < 2%
Noticeable difference: 1%, but keep in mind that it varies a lot by unit, even of the same model; yours likely will not end up exactly like ours.
:
2.259 %

The black uniformity isn't that bad for an IPS TV, but most VA LED TVs will look better.

7.7 Pre Calibration
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What it is: TV's color accuracy before a full calibration. Only the picture mode and backlight level were changed.
When it matters: All video on an uncalibrated TV. This represents most people's use cases.
Score components:
LG UF6400 Pre Calibration Picture LG UF6400 Pre Gamma Curve Picture LG UF6400 Pre Color Picture
White Balance dE
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What it is: Average inaccuracy of shades of gray.
When it matters: Overall color temperature of all video.
Good value: < 3
Noticeable difference: 1
:
3.88
Color dE
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What it is: Average inaccuracy of colors.
When it matters: All colors.
Good value: < 3
Noticeable difference: 1
:
4.2648
Gamma
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What it is: Brightness of shades of gray.
When it matters: Shadows.
Good value: Between 2.1 and 2.3 (our target is 2.2)
Noticeable difference: 0.1
:
1.88

9.7 Post Calibration
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What it is: TV's color accuracy after a full calibration with a spectrophotometer.
When it matters: All video on a TV that has been professionally calibrated. This isn't that useful, because most TVs can achieve a pretty good calibration if you spend enough time on them.
Score components:
LG UF6400 Post Calibration Picture LG UF6400 Post Gamma Curve Picture LG UF6400 Post Color Picture
White Balance dE
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What it is: Average inaccuracy of shades of gray.
When it matters: Overall color temperature of all videos.
Good value: < 3
Noticeable difference: 1
:
0.3
Color dE
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What it is: Average inaccuracy of colors.
When it matters: All colors.
Good value: < 3
Noticeable difference: 1
:
0.6771
Gamma
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What it is: Brightness of shades of gray.
When it matters: Shadows.
Good value: Between 2.1 and 2.3 (our target is 2.2)
Noticeable difference: 0.1
:
2.21

8.0 480p Input
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What it is: Quality of a 480p input.
When it matters: Standard definition TV, DVDs.
Score components: Subjectively assigned
LG UF6400 480p Picture

DVDs will looks good once upscaled.

8.0 720p Input
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What it is: Quality of a 720p input.
When it matters: HD channels, some streaming videos.
Score components: Subjectively assigned
LG UF6400 720p Picture

Cable TV and other 720p content also look good on this TV.

9.0 1080p Input
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What it is: Quality of a 1080p input.
When it matters: Blu-rays, streaming video, video files, video games.
Score components: Subjectively assigned
LG UF6400 1080p Picture

Blu-rays looks sharp once upscaled.

8.0 4k Input
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What it is: Quality of a 4k UHD input.
When it matters: Streaming video, UHD Blu-rays, some PCs.
Score components: Subjectively assigned
LG UF6400 4k Picture

This TV doesn't display true 4k resolution. It includes a white pixel in its pixel substructure. It isn't apparent from farther away, but can be obvious from up close, like if you use the TV as a PC monitor. Text can look blurry.

6.6 Color Gamut
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What it is: How many colors the TV can display.
When it matters: HDR content. Includes some streaming videos and UHD Blu-rays.
Score components:
Wide Color Gamut
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What it is: Whether the TV has an option to enable wide color gamuts.
When it matters: HDR content. Includes some streaming videos and UHD Blu-rays.
:
No
LG UF6400 Color Gamut DCI-P3 Picture
DCI P3 xy
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What it is: Coverage of the DCI P3 colorspace on CIE 1931 xy.
When it matters: DCI P3 content. Includes HDR, UHD Blu-rays.
Good value: > 90%
Noticeable difference: 5%
:
74.28 %
DCI P3 uv
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What it is: Coverage of the DCI P3 colorspace on CIE 1976 u' v'.
When it matters: DCI P3 content. Includes HDR, UHD Blu-rays.
Good value: > 90%
Noticeable difference: 5%
:
82.18 %
Rec 2020 xy
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What it is: Coverage of the Rec.2020 colorspace on CIE 1931 xy.
When it matters: Rec.2020 content. Includes HDR, UHD Blu-rays.
Good value: > 90%
Noticeable difference: 5%
:
52.16 %
Rec 2020 uv
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What it is: Coverage of the Rec.2020 colorspace on CIE 1976 u' v'.
When it matters: Rec.2020 content. Includes HDR, UHD Blu-rays.
Good value: > 90%
Noticeable difference: 5%
:
57.05 %

6.5 Reflections
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What it is: How much light is reflected by the TV.
When it matters: Bright rooms.
Score components: Subjectively assigned
LG UF6400 Reflections Picture LG UF6400 Bright Room Picture
Reflection
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What it is: Ratio of ambient light reflected by the TV.
When it matters: Ambient light in the room.
Good value: < 1%
Noticeable difference: 0.5%
:
1.9 %
Screen Finish
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What it is: Type of coating on the screen.
When it matters: Bright objects in the direct reflection path (for example, opposite the TV).
Good value: Glossy is good for ambient light, but not for direct reflections.
:
Semi-gloss

Direct light produces rainbow reflections.
While it can get bright enough, the TV isn't able to overcome strong light. It also get a yellow tint when there is a lot of light in the room.

0 3D
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What it is: Optional 3D video capability on TV.
When it matters: 3D movies and videos.
Score components: Subjectively assigned
3D
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What it is: If it can display a picture in 3D.
When it matters: 3D movies & videos.
:
No
3D Type
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What it is: The 3D technology used by the TV.
When it matters: 3D movies & videos.
Good value: Active have better resolution, but flickers. Passive is more comfortable, but loses half the vertical resolution.
:
No

Pixels
LG UF6400 Pixels Picture

The less accurate RGBW 4k panel of the LG UF6400 adds a white pixel, which can be seen in this close-up picture of the screen.

7.1

Motion

Here again, the LG UF6400 is average. The motion blur trail isn't too long, but the uniformity of the screen is bad, which could be apparent on playing surfaces, since those are mostly solid colors.

7.7 Motion Blur
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What it is: Amount of blur on fast movement.
When it matters: Sports, video games.
Score components:
LG UF6400 Motion Blur Picture LG UF6400 Response Time Chart
Response Time
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What it is: How quickly pixels can change color.
When it matters: Fast movement.
Good value: < 20ms
Noticeable difference: 10ms
:
18.8 ms
Overshoot
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What it is: When TV’s pixels adjust too far; how quickly they come back.
When it matters: Fast movement.
Good value: < 10ms
Noticeable difference: 10ms
:
0 ms

The motion blur isn't particularly bad, and it won't be a problem for most content.

2.8 Image Flicker
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What it is: Luminosity pattern when displaying images
When it matters: Sports, video games, when TV is used as a PC monitor
Score components:
LG UF6400 Backlight Picture
PWM Dimming Frequency
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What it is: Flickering pattern at different luminosities.
When it matters: For people sensitive to flickering.
Good value: N/A or high frequencies (> 300 Hz)
:
120 Hz
BFI
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What it is: Option to turn screen black between frames
When it matters: Reduces eye tracking blur in sports or video games
Good value: Yes
:
No
BFI Frequency
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What it is: Lowest possible frequency of flickering pattern
When it matters: Reduces eye tracking blur in sports or video games
Good value: 60 Hz
:
120 Hz
BFI In Game Mode
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What it is: Option to insert black frames when in the best settings for gaming
When it matters: Reducing eye tracking blur for video games
Good value: Yes
:
No

7.1 24p Playback
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What it is: Whether 24p content can play without any judder.
When it matters: Only 24p content (mostly just movies).
Judder-free 24p
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What it is: Judder-free movies over 24p signal.
When it matters: Blu-ray and DVD movies; 24 hz PC signal.
:
Yes
Judder-free 24p via 60p
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What it is: Judder-free movies over 60p signal.
When it matters: Movies from streaming devices (Apple TV, Fire TV, etc.); 60 hz PC signal.
:
No
Judder-free 24p via 60i
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What it is: Judder-free movies over 60i signal.
When it matters: Movies from cable/satellite boxes.
:
No

For 24p sources like Blu-ray, the TV is able to remove judder correctly. Unfortunately, movies over cable or from some streaming services will still have judder inconsistently. Since this is a 60 hz TV and it has TruMotion, it can only interpolate signals under 60 hz.

5.0 Motion Interpolation
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What it is: Also known as 'Soap Opera Effect'. It is an optional feature that increases the frame rate of the video, smoothing movement.
When it matters: If you like the look of smoothed video. Not everyone does.
Motion Interpolation (30 fps)
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What it is: Whether the TV can take a 30 fps input and heighten the frame rate to at least 60 fps.
When it matters: 30 fps or lower videos. Includes movies, TV shows, some video games.
:
Yes
LG UF6400 Motion Interpolation (30 fps) Picture
Motion Interpolation (60 fps)
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What it is: Whether the TV can take a 60 fps input and heighten the frame rate to at least 100 fps.
When it matters: 60 fps videos. Includes some video games, some sports channels.
:
No

6.2

Inputs

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Score components:

Only casual gaming would be suitable on this TV, since the input lag is average-high. Any competitive gaming should be avoided. The lag is even more apparent when using the TV as a PC monitor. Combined with the fact that 4k doesn't look that sharp up-close, this TV wouldn't be great as a PC monitor (even though it is compatible with most PC inputs).

5.9 Input Lag
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What it is: Delay between input and onscreen reaction.
When it matters: Video games; when TV is used as PC monitor.
1080p @ 60Hz
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What it is: Lowest input lag possible on TV with a 1080p @ 60Hz input.
When it matters: Video games and also when TV is used as PC monitor.
Good value: < 40ms
Noticeable difference: 15ms
:
56.1 ms
1080p With Interpolation
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What it is: Lowest input lag when the motion interpolation feature is turned on.
When it matters: When you want to play video games with the Soap Opera Effect enabled.
Good value: < 40ms
Noticeable difference: 15ms
:
129.2 ms
1080p @ 60Hz Outside Game Mode
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What it is: Input lag in picture modes other than the specific game mode.
When it matters: For playing video games while retaining access to all features of the TV.
Good value: < 40ms
Noticeable difference: 15ms
:
71.2 ms
1080p @ 60Hz @ 4:4:4
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What it is: Lowest input lag possible on TV when displaying 1080p @ 60Hz @ 4:4:4
When it matters: PC monitor.
Good value: < 40ms
Noticeable difference: 15 ms
:
56.1 ms
4k @ 60Hz + HDR
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What it is: Lowest input lag possible on TV when displaying 4k @ 60Hz with HDR.
When it matters: HDR Video games.
Good value: < 40ms
Noticeable difference: 15 ms
:
N/A
4k @ 60Hz @ 4:4:4 + 8 bit HDR
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What it is: Lowest input lag possible on TV when displaying 4k @ 60Hz @ 4:4:4 with HDR enabled at 8 bit
When it matters: PC Monitor with an HDR capable graphic card
Good value: < 40ms
Noticeable difference: 15 ms
:
N/A

Under game mode, the TV is responsive enough for casual gaming, but any hardcore players will feel a bit of lag on their controller inputs. Compared to other 2015 TVs, the input lag is average-high.

8.0 Supported Resolutions
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What it is: Different resolutions supported by TV.
When it matters: PC monitor usage.
Score components:
  • 20% 1080p @ 60Hz @ 4:4:4
  • 20% 1080p @ 120Hz
  • 20% 4k @ 30Hz @ 4:4:4
  • 20% 4k @ 60Hz
  • 20% 4k @ 60Hz @ 4:4:4
1080p @ 60Hz @ 4:4:4
Show Help
What it is: Crisp text on 1060p @ 60 hz signal.
When it matters: PC productivity and 60 fps gaming.
:
Yes
1080p @ 120Hz
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What it is: 120 fps 1080p signal supported.
When it matters: PC gaming.
:
No
4k @ 30Hz @ 4:4:4
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What it is: Crisp text on 4k @ 30 hz signal.
When it matters: PC productivity and gaming.
:
Yes
4k @ 60Hz
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What it is: 60 fps 4k signal supported.
When it matters: PC productivity and gaming.
:
Yes
4k @ 60Hz @ 4:4:4
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What it is: Crisp text on 4k @ 60 hz signal.
When it matters: Productivity and 60 fps gaming in 4k.
:
Yes

Most of the modes tested work on this TV except for 1080p@120Hz. To achieve 4k @ 60Hz turn on 'HDMI Ultra HD Deep Color'. To add chroma 4:4:4, enable 'HDMI-PC' under the picture menu. Unfortunately, if you use the TV as a PC monitor, the input lag (same as in game mode) will be quite apparent. Even more so for games like first person shooters, which require fast reflexes.

Side Inputs
Rear Inputs
Total Inputs
HDMI : 2
USB : 1
Digital Optical Audio Out : 1
Analog Audio Out 3.5mm : 0
Analog Audio Out RCA : 0
Component In : 1 (shared)
Composite In : 1 (shared)
Tuner (Cable/Ant) : 1
Ethernet : 1
DisplayPort : 0
IR In : 0
SD/SDHC : 0

Inputs Specifications
HDR10
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What it is: Standard HDR format.
When it matters: Most common format. All UHD Blu-ray discs are required to have it.
:
No
Dolby Vision
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What it is: Better format, due to its dynamic nature.
When it matters: Currently, only available via streaming.
:
No
5.1 Passthrough ARC Dolby Digital
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What it is: TV can receive and pass Dolby Digital 5.1 signal to receiver via HDMI ARC.
When it matters: 5.1 audio on DVDs and Blu-rays.
:
Yes
5.1 Passthrough ARC DTS
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What it is: TV can receive and pass DTS 5.1 signal to receiver via HDMI ARC.
When it matters: 5.1 audio on DVDs and Blu-rays.
:
Yes
5.1 Passthrough Optical Dolby Digital
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What it is: TV can receive and pass Dolby Digital signal to receiver via digital optical.
When it matters: 5.1 audio on DVDs and Blu-rays.
:
Yes
5.1 Passthrough Optical DTS
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What it is: TV can receive and pass DTS signal to receiver via digital optical.
When it matters: 5.1 audio on DVDs and Blu-rays.
:
Yes
HDMI 2.0 Full Bandwith : Yes
ARC : Yes (HDMI 2)
USB 3 : No
HDCP 2.2 : Yes
CEC : Yes
MHL : No
Variable Analog Audio Out : No

6.2

Sound Quality

The sound of the LG UF6400 is like that of most other TVs. It can get loud enough without much distortion, but anyone who cares about sound would benefit from using a dedicated soundbar or speaker system.

Note: Sound Quality test for TVs reviewed before 2017 was performed at 75dB, 85dB, and Max SPL. Starting 2017, the target SPL levels have been changed to 70dB, 80dB, and Max dB SPL.

6.5 Frequency Response
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What it is: Sound level at different frequencies.
When it matters: For balanced sound.
Score components:
LG UF6400 Frequency Response Picture
Std. Dev. @ 70
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What it is: Variance of the sound level at different frequencies.
When it matters: 70 dB.
Good value: < 4 dB
Noticeable difference: 2 dB
:
4.55 dB SPL
Std. Dev. @ 80
Show Help
What it is: Variance of the sound level at different frequencies.
When it matters: 80 dB.
Good value: < 4 dB
Noticeable difference: 2 dB
:
4.75 dB SPL
Std. Dev. @ Max
Show Help
What it is: Variance of the sound level at different frequencies.
When it matters: Max volume.
Good value: < 4 dB
Noticeable difference: 2 dB
:
7.64 dB SPL
Max
Show Help
What it is: Max volume on the TV at a distance of 1 meter.
When it matters: For listening to loud audio.
Good value: > 90 dB
Noticeable difference: 2 dB
:
90.3 dB SPL
Low-end Cutoff
Show Help
What it is: How low of a frequency at which the bass starts.
When it matters: Movies; gaming.
Good value: < 50Hz
Noticeable difference: 10Hz
:
89 Hz

Poor frequency response, especially under heavy load, which seems to cause significant pumping and compression. The loudness and bass-extension are decent.

5.6 Total Harmonic Distortion
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What it is: Pureness of a single frequency.
Score components:
LG UF6400 Total Harmonic Distortion Picture
Distortion @ 70
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What it is: Amount of distortion.
When it matters: 70 dB.
Good value: < 0.100
Noticeable difference: 0.100
:
0.037
Distortion @ 80
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What it is: Amount of distortion.
When it matters: 80 dB.
Good value: < 0.100
Noticeable difference: 0.100
:
0.116
Distortion @ Max
Show Help
What it is: Amount of distortion.
When it matters: 85 dB.
Good value: < 0.100
Noticeable difference: 0.100
:
0.096

Decent distortion performance at all levels.

8.5

Smart Features

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Score components: Subjectively assigned
LG UF6400 Smart TV Picture
Smart OS : WebOS

WebOS is a great smart TV platform and has a good amount of available apps. Unfortunately, you don't get the smart remote with this TV, so it isn't the best way to experience the platform. It takes more time to input text, but other than that, the navigation is straightforward. You can read our overview of LG's WebOS here.

0 Ads
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What it is: Whether or not ads can be found on the TV's smart platform.
When it matters: When using the smart features.
Score components:
Ad-free
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What it is: The TV's ability to provide an ad-free experience.
When it matters: When using the smart features.
:
No
Opt-out
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What it is: Whether you can opt out of the ad services or not. A TV only passes this test if it allows you to remove them completely, not only disable the personalized advertising.
When it matters: When using the smart features.
:
No

Remote
LG UF6400 Remote Picture
Remote : Basic

Misc
Power Consumption : 36 W
Power Consumption (Max) : 57 W
Firmware : 03.10.21

Conclusion
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Unfortunately, the LG UF6400 isn't a great TV. Movie lovers will find that the picture lacks some punch and gamers won't be satisfied with the responsiveness. Even if the TV is compatible with most PC inputs, the lag and somewhat-blurry 4k resolution will still make it a no-go. The only scenario where this TV could be viable is in an average-lit room with off-axis seating. For most people's needs, there is a better TV than this one.

Usage Ratings
6.6Mixed Usage
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What it is General purpose. The TV will be used for a variety of content and usages. Movies at night, TV shows during the day, video games from time to time, etc.
Score components:
6.1Movies
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What it is Movies in the dark. The TV will be used for watching movies in a controlled environment, directly in front, in a home theater way. Mostly only high quality content, like Blu-rays, UHD Blu-rays, streaming and a little bit of HDR.
Score components:
7.0TV Shows
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What it is TV Shows in a bright living room. The TV will be used in to watch TV shows, in a bright room during the day, from multiple viewing positions at different angles. The content watched has an average quality: cable, streaming, SD channels, etc.
Score components:
6.9Sports
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What it is Sports in a living room. The TV will be used to watch sports during the day, like football or hockey. Usually watched with a group, so from multiple viewing position.
Score components:
7.0Video Games
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What it is Video games. The TV will be used to play video games, directly in front, in a controlled light environment. Usually fast games, like online FPS, where motion blur and input lag is important.
Score components:
5.9HDR Movies
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What it is HDR Movies and TV shows. The TV will be used to watch 4k UHD HDR content, with a wide color gamut and a high peak brightness. Either via UHD Blu-rays or HDR streaming.
Score components:
4.3HDR Gaming
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What it is HDR Gaming. The TV will be used to play HDR video games using consoles that support it or on current generation gaming PCs. Xbox One S, PS4 Pro, GTX 10 series and AMD RX series graphics cards.
6.5PC Monitor
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What it is PC Monitor. The TV will be used as a PC monitor, from 2-3 feet away, either for productivity purposes or gaming. Sharp text is important, as well as a high resolution.
Score components:
Questions Found an error?

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Questions & Answers

3 ANSWERED QUESTIONS
8
So you are not going to provide the calibration settings, despite you actually having these metrics?
The calibration settings are always posted in the second tab of our reviews (direct link).
8
What does ultra hdmi deep color do and will it help or effect blu Ray or gaming on a ps4 or should it be left off?
'HDMI Deep Color' won't make much of a difference but it can help smooth out some gradations. Since the TV support it, you can turn it on if your source device also support it, like for your PS4.
6
In the Video Games section you rated a 6.9 Input Lag and 8.0 for PC Monitor, netting the overall section a 7.3. Not sure what formula you are using, but a simple mean would yield 7.45. Anyways, I noticed that the recommended mid-range LG TV (UF8500) was rated the same exact values for Input Lag and PC Monitor. However, the resulting Video Games score was a 7.7
Can you tell me why the recommended TV netted a better score with the exact same criteria as the more inferior TV?
We also take the amount of motion blur into account when calculating the score for the Video Games section, so that's why the scores are a little different than you might expect. You can see our full scoring breakdown here.
We are not taking any more questions for this product because we no longer have it in our lab.