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Sony X850F TV REVIEW

This tv was replaced by the Sony X850G

Type : LED
Sub-Type
:
IPS (except 85")
Resolution : 4k

The Sony X850F is a good 4k TV with an IPS panel. It can get bright to overcome glare and handles reflection well in a bright room but it has a very low contrast ratio so blacks appear gray when viewed in a dark room. The picture quality is decent but remains accurate when viewed at an angle which is good for those with wide seating. It also has a fast response time, which is great for watching fast-paced content. Unfortunately, Android TV isn't as streamlined or intuitive as other platforms.

Pros
  • Feels responsive with low input lag
  • Great motion handling
  • Image remains accurate at an angle
Cons
  • Blacks appear gray and blotchy in a dark room

Test Results
Design 8.5
Picture Quality 7.3
Motion 8.5
Inputs 8.7
Sound Quality 6.1
Smart Features 8.0
  1. Update 2/28/2019: Converted to Test Bench 1.3. Learn more about our versioned test bench system here.
  2. Update 6/12/2018: A note for Xbox One X and Xbox One S owners: 1080p @ 120 Hz from the Xbox is only supported on this TV when the Xbox's connection type is changed from Auto-detect (Recommended) to HDMI, but unfortunately in this mode 4k and HDR aren't supported.
  3. Update 6/8/2018: The X850F has been retested, and can play 24p movies from all sources at the correct cadence.
  4. Update 5/2/2018: The color gamut was erroneously measured at a 50% stimulus. It has been remeasured at 75% stimulus to be in line with our other TVs.

Check Price

65" XBR65X850F
SEE PRICE
Amazon.com
75" XBR75X850F
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B&H
85" XBR85X850F
SEE PRICE
Amazon.com

Summary

  • 7.7 Mixed Usage
  • 6.4 Movies
  • 8.3 TV Shows
  • 8.2 Sports
  • 8.0 Video Games
  • 6.4 HDR Movies
  • 7.5 HDR Gaming
  • 8.4 PC Monitor
Mixed Usage 7.7

Good TV for a range of usages. Blacks appear gray and blotchy when viewed in a dark room such as watching movies at night, but in a bright room, the reflection handling is good and the TV can get bright to overcome glare. Image also remains accurate when viewed at an angle, which is good. Input lag is low and motion handling is great, which is great for PC use or gaming. The TV supports HDR, but it can't produce very vivid colors or bright highlights to take advantage of it.

Movies 6.4

Mediocre pick for watching movies in a dark room. Native contrast is low and the TV doesn't support local dimming so blacks appear gray and blotchy when viewed in a dark room. Movies are smooth when played from a Blu-ray player or native apps, but some small stutter may be noticeable when watching movies over cable.

TV Shows 8.3

Great choice for watching TV in a bright room. Image remains accurate when viewed at an angle, which is good for those with wide seating. The Sony X850F can get bright to overcome ambient glare which is great, and anti-reflective coating works well to reduce distracting reflections. Unfortunately, although the Android TV smart platform is very versatile, it is less intuitive and slower than other platforms for casual watching.

Sports 8.2

Great TV for watching sports in a bright room. Motion handling is great, thanks to the fast response time so only a short trail is seen behind a fast moving puck or football. Picture quality is only decent, but the image remains accurate when viewed at an angle which is good. The screen can get bright to overcome glare, and TV is great at handling reflections so it is a great fit for a bright room.

Video Games 8.0

Great TV for gamers. Input lag is low, so the TV feels responsive, which is great. Motion handling is also great, and only a short trail can be seen behind fast-moving objects. Picture quality is only decent though, and blacks appear gray and blotchy in a dark room.

HDR Movies 6.4

Mediocre TV for watching HDR movies. Picture quality is only mediocre, as blacks appear gray and blotchy in a dark room. Movies from a Blu-ray player or Netflix are smooth, but the X850F doesn't have a very wide color gamut and can't produce bright highlights.

HDR Gaming 7.5

Better than average for HDR gaming. The TV feels responsive due to low input lag and great motion handling. Unfortunately, blacks appear gray in a dark room, and the TV can't produce a very wide color gamut or bright highlights for HDR. Also, it doesn't support local dimming to improve the dark scene performance.

PC Monitor 8.4

Great option for a monitor. Image remains accurate when viewed at an angle, which is great when viewing the edge of the screen from close up for PC use. The TV supports chroma 4:4:4 for clear text on all backgrounds, and it feels responsive due to low input lag and great motion handling.

Compared to other TVs

Top left: LG B6 (OLED55B8P). Bottom left: Samsung MU8000 (UN55MU8000). Middle: Sony X850F (XBR65X850F). Top right: Sony X850E (XBR65X850E). Bottom right: Sony X900F (XBR55X900F).  Unlike our other photographs, this picture wasn't taken under a controlled environment, so do not draw conclusions from it.

The Sony X850F is a good pick for a bright room with wide seating as the low native contrast ratio makes blacks appear gray in a dark room, but the image remains accurate when viewed at an angle. See our picks below for how it compares to the competition. See our recommendations for the best smart TVs and the best flatscreen TVs.

Sony X900F
55"
SEE PRICE
Amazon.com

The Sony X850F is more suitable for a large room with wide seating arrangement as it has better viewing angles. If you will be sitting right in front of the TV, then the Sony X900F is a much better choice. The X900F has higher native contrast ratio, and better local dimming and black uniformity that produce deep blacks in a dark room. Also, the X900F has better HDR peak brightness that allows it to display a rich and vivid HDR content much better than the X850F. Finally, the X900F has a faster response time which is great for fast action.

Sony X850G
65"
SEE PRICE
Amazon.com

There are very few differences between the Sony X850F and the Sony X850G. The 2019 X850G has much lower input lag, and it supports eARC. Other than that, these two TVs perform very similarly.

Samsung NU8000
55"
SEE PRICE
Amazon.com

If you enjoy watching movies or playing games in a dark room with seating right in front, then the Samsung NU8000 is a better choice; however, if you have a large bright room with wide seating, then the Sony X850F is a better choice due to the better viewing angles and better reflection handling. The Samsung NU8000, on the other hand, is much better for watching movies as it has better blacks in a dark room. It's also much better for gaming due to lower input lag, faster response time, and FreeSync variable refresh rate technology.

Sony X800G
55"
SEE PRICE
Amazon.com

The Sony X850F is better than the X800G, but the differences might not matter as much for everyone. The X850F has better reflection handling, great for bright rooms, and it can remove judder from all sources, whereas the X800G can only remove judder from true 24p sources.

Sony X750F
55"
SEE PRICE
Amazon.com

The Sony X850F is better than the Sony X750F. The Sony X850F can get brighter and has better reflection handling, so you can place it in a brighter room without issues. The Sony X850F also has a faster response time, can remove 24p judder, and has a motion interpolation feature. Finally, the X850F has a lower input lag, which is great for video games. The Sony X750F, on the other hand, has better color accuracy out of the box.

Samsung Q6FN/Q6/Q6F QLED 2018
55"
SEE PRICE
Amazon.com

Although these are two different types of TVs, most people will agree that the Samsung Q6FN is better than the Sony X850F overall. The Samsung Q6FN has a VA panel and can offer a much better dark room performance if you're seated straight in front, while the X850F has wider viewing angles due to its IPS panel. The Sony X850F can handle reflections a little better and has no visible flicker, whereas the Q6FN supports FreeSync and has a lower input lag.

Sony X830F
60"
SEE PRICE
B&H

If you've got a bright room with wide seating, then the Sony X850F is a better choice due to the IPS panel and the good viewing angles. But for a dark room with seating directly in front, the Sony X830F is better because of the higher native contrast ratio the VA panel has. The Sony X850F also has a lower input lag for those who play video games and somewhat better reflection handling if you place it in a room with many lights. The Sony X830F, on the other hand, has a slightly faster response time, and thus displays less blur on fast-moving content like sports.

LG SK8000
55"
SEE PRICE
B&H

The LG SK8000 and the Sony X850F both have very similar performance. The Sony X850F can get brighter in SDR and is more suitable for a brighter room, whereas the SK8000 has local dimming support to enhance dark room performance. The LG is also more responsive, due to the lower input lag.

Sony X850E
65"
SEE PRICE
Amazon.com

If you've got a bright room with wide seating, then the Sony X850F is a better choice due to its better viewing angles and better reflection handling. But for a dark room with seating directly in-front, the Sony X850E is better. The Sony X850F has marginally better input lag for video games and HDR gaming and is slightly better as a PC monitor. On the other hand, the Sony X850E has a much better contrast ratio and better black uniformity that make it a better choice for movies in a dark room.

Samsung NU7100
55"
SEE PRICE
B&H

These two TVs have different panels, each with its advantages and disadvantages. The Sony X850F has an IPS panel and is more suitable if you have a room with a wide seating arrangement. The Sony X850F can also handle reflections better if your room has many light sources, and is flicker-free for those who are sensitive to flicker. Finally, it has a wider color gamut and better color volume for HDR enthusiasts. The Samsung NU7100 is more suitable for a dark room thanks to its VA panel and higher contrast ratio. Also, the Samsung NU7100 has marginally lower input lag, which is great for casual gaming.

Samsung Q60/Q60R QLED
55"
SEE PRICE
Amazon.com

The Sony X850F and the Samsung Q60R are similar but use different panel types, so they each have their own advantages and disadvantages. The Sony X850F uses an IPS panel, and has much better viewing angles, but worse dark room performance. The Samsung Q60R has a much better native contrast ratio, lower input lag, and a more versatile black frame insertion feature. The Q60R also supports FreeSync variable refresh rate.

LG B8 OLED
55"
SEE PRICE
Amazon.com

The Sony X850F and LG B8 use different panel technologies, each with their advantages and disadvantages. The X850F has an IPS panel and can get brighter than the B8, whereas the B8 has much better in a dark room performance, as the OLED panel delivers perfect blacks. The B8 has a faster response time that delivers motion with less blur trail but with more stutter. The B8 has the risk of burn-in when exposed to static content, whereas the X850F is immune to it.

LG SM8600
55"
SEE PRICE
B&H

The Sony X850F and the LG SM8600 both have very similar performance. The Sony is more suitable for a brighter room as it can get brighter in SDR and can also display HDR content with bright highlights. The LG has a slightly better dark room performance with a higher contrast ratio and a local dimming feature. The SM8600 also has lower input lag, which is great for gamers, and a better black frame insertion implementation that can make the motion crisper.

Sony X950G
55"
SEE PRICE
Amazon.com

The Sony X950G and the Sony X850F use different panel types, each with strengths and weaknesses. Overall, the X950G is much better than the X850F. The X950G has a much better dark room performance, but the image degrades when viewed from the side. The X850F maintains a more accurate image when viewed from the side, at the expense of worse dark room performance.

Sony X900E
55"
SEE PRICE
Amazon.com

The Sony X850F is a better choice for a room with wide seating due to its better viewing angles. The Sony X900E, on the other hand, is a better choice if you have a darker room with direct in-front seating. The Sony X900E can display better blacks due to higher native contrast ratio and better local dimming. Also, if you want a brighter TV to enjoy TV shows, then the Sony X900E is a better choice as it has better SDR peak brightness.

LG UK6570
75"
SEE PRICE
B&H

The Sony X850F and the LG UK6570 are very similar overall. The X850F is brighter in SDR and HDR and has a wide color gamut. The X850F has better overall motion handling, with slightly faster response time, nearly flicker-free backlight, and better motion interpolation thanks to the 120 Hz panel. The LG UK6570 has much lower input lag, great for gaming or use as a PC monitor. The 85" X850F uses a VA panel, compared to the 86" UK6570 that has an IPS panel, so the XBR85X850F likely will perform better in a dark room.

LG SM9500
65"
SEE PRICE
Amazon.com

The Sony X850F is marginally better than the LG SM9500. The Sony has better gray uniformity, which is great if you're a sports fan. The X850F is also flicker-free, which is important for those that are bothered by flicker. The SM9500, on the other hand, can get brighter and is suitable for a very bright room. The LG has a local dimming feature that can provide some improvement with the appearance of blacks in a dark room. The LG also has a lower input lag, which is good news to gamers, but also shows some signs of temporary image retention.

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Test Results

Stand

The stand on the X850F is unlike any other Sony TV we have reviewed. It is similar to the stand on the Samsung MU6100. It is made entirely of plastic with an aluminum finish. On our 65" model, we found them to cause the TV to wobble if it is knocked.

The footprint of the 65" TV stand: 12.0" x 43.4"

Back
Wall Mount : VESA 300x300

Similar to the X850E, the back of the TV is quite basic. Similar to the X900F there is only very basic cable management through the legs of the TV. The back is almost identical to the X900F.

Borders
Borders : 0.39" (1.0 cm)

The borders of the TV look good. While slightly thicker than the 55" X900F they are still quite thin.

Thickness
Max Thickness : 2.13" (5.4 cm)

The Sony XBR65X850F has more of a uniform thickness than the X900F. It won't stick out from the wall much when mounted.

Temperature
Maximum Temperature
:
109 °F (43 °C)
Average Temperature
:
93 °F (34 °C)

The bottom edge of the TV gets warm to the touch due to the edge light LEDs. There are also a few places along the back that get warm to the touch, but this should't be an issue.

7.5 Build Quality

The X850F feels well constructed, despite being made almost entirely of plastic. There are no obvious gaps or issues. The tabs along the back of the legs for cable management are just bent plastic. While it hasn't caused any issues for us, this could break with repeated flexing.

5.8 Contrast
Native Contrast
:
894 : 1
Contrast with local dimming
:
N/A

Disappointing contrast ratio on the X850F. It has an IPS type panel similar to the X850D. Dark scenes will not look their best especially when playing in a dark room.

We tested the 65" model, but it is highly likely that the 85" will have a VA type panel, which we would expect to have at least a 3000:1 contrast ratio.

0 Local Dimming
Local Dimming
:
No
Backlight
:
Edge

There is no local dimming feature on the X850F. The video is for reference only.

8.1 SDR Peak Brightness
SDR Real Scene Peak Brightness
:
371 cd/m²
SDR Peak 2% Window
:
397 cd/m²
SDR Peak 10% Window
:
396 cd/m²
SDR Peak 25% Window
:
396 cd/m²
SDR Peak 50% Window
:
396 cd/m²
SDR Peak 100% Window
:
396 cd/m²
SDR Sustained 2% Window
:
396 cd/m²
SDR Sustained 10% Window
:
396 cd/m²
SDR Sustained 25% Window
:
395 cd/m²
SDR Sustained 50% Window
:
395 cd/m²
SDR Sustained 100% Window
:
396 cd/m²
SDR ABL
:
0.000

Very good peak brightness in SDR. There is almost no difference in brightness across the windows sizes, which is good. The TV is bright enough for most rooms. It is brighter than last year's X850E and LG's SJ8500, but dimmer than this year's X900F.

7.2 HDR Peak Brightness
HDR Real Scene Peak Brightness
:
457 cd/m²
HDR Peak 2% Window
:
521 cd/m²
HDR Peak 10% Window
:
521 cd/m²
HDR Peak 25% Window
:
521 cd/m²
HDR Peak 50% Window
:
521 cd/m²
HDR Peak 100% Window
:
521 cd/m²
HDR Sustained 2% Window
:
520 cd/m²
HDR Sustained 10% Window
:
521 cd/m²
HDR Sustained 25% Window
:
521 cd/m²
HDR Sustained 50% Window
:
521 cd/m²
HDR Sustained 100% Window
:
520 cd/m²
HDR ABL
:
0.000

Decent HDR brightness. It is brighter than the X850E. Most people will find the highlights bright enough when watching movies in HDR, but HDR content will look best on a brighter screen like the X900F.

7.4 Gray Uniformity
50% Std. Dev.
:
3.555 %
50% DSE
:
0.190 %
5% Std. Dev.
:
0.566 %
5% DSE
:
0.084 %

Better than average screen uniformity. No serious issues with dirty screen effect, which is good for watching sports or other content with large areas of uniform colors. This TV is brightest in the center and the corners are dark, which is common for TVs and isn't as distracting as uniformity issues near the center or brighter edges.

7.7 Viewing Angle
Color Washout
:
29 °
Color Shift
:
64 °
Brightness Loss
:
38 °
Black Level Raise
:
70 °
Gamma Shift
:
44 °

Good viewing angle. Color saturation and black levels remain good even if sitting on a wide couch or with side seating, but brightness drops sharply if sitting to the side.

We tested the 65" model which uses an IPS panel. It is highly likely that the 85" model uses a VA type panel which would have worse viewing angles.

5.8 Black Uniformity
Native Std. Dev.
:
2.113 %
Std. Dev. w/ L.D.
:
N/A

Disappointing black uniformity. There is some obvious clouding especially around the edges. The X850F does not handle dark scenes well and would not be recommended for a dark room.

Clouding is more visible when displaying bright objects in dark scenes, since this TV does not have a local dimming feature.

8.6 Reflections
Screen Finish
:
Semi-gloss
Total Reflections
:
3.5 %
Indirect Reflections
:
0.6 %

The X850F has a very similar to finish to the X900F. It does not diffuse reflections as much as some other TVs.

6.7 Pre Calibration
White Balance dE
:
4.42
Color dE
:
3.10
Gamma
:
2.15
Color Temperature
:
6114 K
Picture Mode
:
Custom
Color Temp Setting
:
Expert 1
Gamma Setting
:
0

Average color accuracy out of the box with 'Custom', 'Game', or 'Graphics' mode. Color temperature is far from our target of 6500K, so most colors have more of a yellow tint. Gamma is very close to our target of 2.2.

9.2 Post Calibration
White Balance dE
:
0.26
Color dE
:
2.17
Gamma
:
2.19
Color Temperature
:
6488 K
White Balance Calibration
:
10 point
Color Calibration
:
No
Auto-Calibration Function
:
No

White balance is near perfect post calibration and color is good. Color temperature is very close to our target as is gamma. 'Custom' picture mode provided the best results.

You can see our recommended settings here.

8.0 480p Input

Older 480p content is upscaled well. There are some minor artifacts but the TV handles it well.

8.0 720p Input

Upscaling of 720p is handled well. There is some softness but the image is clear.

9.0 1080p Input

1080p content from a Blu-ray or game console is upscaled well.

10 4k Input

There are no issues with native 4k content.

7.7 Color Gamut
Wide Color Gamut
:
Yes
DCI P3 xy
:
84.41 %
DCI P3 uv
:
92.10 %
Rec 2020 xy
:
61.99 %
Rec 2020 uv
:
70.12 %

The HDR color gamut of the X850F is good, although Rec 2020 coverage is limited. The TV has difficulty producing deeply saturated greens especially. Most scenes won't have overly saturated colors, but in very colorful scenes such as a sunset or an ocean scene the TV's limited color gamut will be noticeable.

The HDR EOTF in the 'Cinema Pro' picture mode follows the target PQ curve fairly well until it rolls off at the TV's peak brightness. The EOTFs in 'Game' and 'PC' mode are very similar to that of 'Cinema Pro', which is good.

Update 05/02/2018: The color gamut was erroneously measured at a 50% stimulus. It has been remeasured at 75% stimulus to be in line with our other TVs. It now measures slightly higher, and meets our threshold for a wide color gamut TV.

6.3 Color Volume
Normalized DCI P3 Coverage ITP
:
71.5 %
10,000 cd/m² DCI P3 Coverage ITP
:
34.8 %
Normalized Rec 2020 Coverage ITP
:
54.8 %
10,000 cd/m² Rec 2020 Coverage ITP
:
26.6 %

Below average color volume. The TV has difficulty displaying deep, dark colors due to the lack of local dimming and low native contrast ratio. It does not cover either color space very well.

8.3 Gradient
Color Depth
:
10 Bit
Red (Std. Dev.)
:
0.123 dE
Green (Std. Dev.)
:
0.116 dE
Blue (Std. Dev.)
:
0.101 dE
Gray (Std. Dev.)
:
0.057 dE

The X850F displays gradients well. There is some banding especially in the dark colors, but not enough to bother most people.

10 Temporary Image Retention
IR after 0 min recovery
:
0.00 %
IR after 2 min recovery
:
0.00 %
IR after 4 min recovery
:
0.00 %
IR after 6 min recovery
:
0.00 %
IR after 8 min recovery
:
0.00 %
IR after 10 min recovery
:
0.00 %

Like most IPS and VA panels, there is no sign of temporary image retention on the X850F.

10 Permanent Burn-In Risk
Permanent Burn-In Risk
:
No

We don't expect IPS panels to have any permanent image retention. The IPS panel in our long term test has not shown any permanent burn-in.

Pixels
8.9 Response Time
80% Response Time
:
3.8 ms
100% Response Time
:
14.9 ms

Great fast response time, good enough for even fast-moving content like sports. Most of the blur in the photo is due to 60 fps persistence; the ghosting trail following the logo is very short, which is excellent. This response time is very similar to the rival Samsung NU8000, but not quite as fast as the higher end Sony X900F.

10 Flicker-Free
Flicker-Free
:
No
PWM Dimming Frequency
:
0 Hz

The X850F has no visible flicker in its backlight, which makes motion appear smooth. This is, unfortunately, a rare thing in TVs; many TVs have 120 Hz PWM flicker, like the LG SJ9500 and Samsung MU8000, which causes duplications during motion (as seen in this MU8000 photo).

6.0 Black Frame Insertion (BFI)
Optional BFI
:
Yes
Min Flicker for 60 fps
:
120 Hz
60 Hz for 60 fps
:
No
120 Hz for 120 fps
:
Yes
Min Flicker for 60 fps in Game Mode
:
120 Hz

The X850F has an optional BFI mode that adds flicker to make motion look more clear. Unfortunately, this flicker is limited to 120 Hz, which causes duplications in 60 fps motion, as seen in the photo; 60 Hz flicker like that of the Samsung NU8000 would be better. The X850F's flicker is activated by setting 'Motionflow' to 'Custom' and increasing the 'Clearness' slider. The X850F does not have the new 'X-Motion Clarity' feature of the X900F, so adding flicker will decrease the TV's brightness.

10 Motion Interpolation
Motion Interpolation (30 fps)
:
Yes
Motion Interpolation (60 fps)
:
Yes

The X850F has a 120 Hz panel and can interpolate lower frame rate content up to 120 fps. This high frame rate greatly improves motion but can appear strange to some (the 'soap opera effect'), and sometimes adds unwanted artifacts during fast motion. Interpolation is activated by setting 'Motionflow' to 'Custom', increasing the 'Smoothness' slider, and setting 'Cinemotion' to 'High'.

7.7 Stutter
Frame Hold Time @ 24 fps
:
26.8 ms
Frame Hold Time @ 60 fps
:
1.8 ms

The TV can show low framerate content smoothly, which is good when watching TV shows and movies. The TV's response time is long enough that completely transitioned frames aren't held on screen for a long time, which reduces the appearance of stutter.

10 24p Judder
Judder-Free 24p
:
Yes
Judder-Free 24p via 60p
:
Yes
Judder-Free 24p via 60i
:
Yes
Judder-Free 24p via Native Apps
:
Yes

The TV can consistently remove judder from all 24p content such as native apps, Blu-ray players, or movies from a cable box which is excellent. The TV removes judder from 24p HDMI sources automatically, but for 60p, 60i and native app sources 'Motionflow' must be set to 'True Cinema' and 'Cinemotion' to 'High' to remove judder.

Update 06/08/2018: The X850F has been retested, and can play movies from 60p or 60i sources at the correct cadence. The text above has been adjusted.

0 Variable Refresh Rate
Native Refresh Rate
:
120 Hz
Variable Refresh Rate
:
No
4k VRR Maximum
:
N/A
4k VRR Minimum
:
N/A
1080p VRR Maximum
:
N/A
1080p VRR Minimum
:
N/A
1440p VRR Maximum
:
N/A
1440p VRR Minimum
:
N/A
VRR Supported Connectors
:
N/A

The TV does not support variable refresh rate features like FreeSync.

8.5 Input Lag
1080p @ 60 Hz
:
27.9 ms
1080p @ 60 Hz Outside Game Mode
:
90.1 ms
1440p @ 60 Hz
:
28.9 ms
4k @ 60 Hz
:
30.0 ms
4k @ 60 Hz + 10 bit HDR
:
30.1 ms
4k @ 60 Hz @ 4:4:4
:
30.0 ms
4k @ 60 Hz Outside Game Mode
:
92.3 ms
4k @ 60 Hz With Interpolation
:
92.3 ms
8k @ 60 Hz
:
N/A
1080p @ 120 Hz
:
13.1 ms
1440p @ 120 Hz
:
13.2 ms
4k @ 120 Hz
:
N/A
1080p with Variable Refresh Rate
:
N/A
1440p with VRR
:
N/A
4k with VRR
:
N/A
8k with VRR
:
N/A
Auto Low Latency Mode (ALLM)
:
No

Low input lag at both 4k and 1080p, a slight improvement over the X850E, though not as good as LG's SJ8500. When in 'Game' or 'Graphics' mode the TV has good low input lag. Input lag is the same even on the low bandwidth HDMI ports 1 & 4.

9.6 Supported Resolutions
1080p @ 60 Hz @ 4:4:4
:
Yes
1080p @ 120 Hz
:
Yes (forced resolution required)
1440p @ 60 Hz
:
Yes (forced resolution required)
1440p @ 120 Hz
:
Yes (forced resolution required)
4k @ 60 Hz
:
Yes
4k @ 60 Hz @ 4:4:4
:
Yes
4k @ 120 Hz
:
No
8k @ 30 Hz or 24 Hz
:
No
8k @ 60 Hz
:
No

The X850F supports all common input signals. Chroma 4:4:4 is supported in 'Game' or 'Graphics' mode. Only HDMI inputs 2 or 3 support 4k @ 60Hz @ chroma 4:4:4 or 4:2:2, and only when 'HDMI Enhanced Format' is enabled.

When in 'Graphics' mode upscaling is done by nearest neighbour when in 1080p @ 60 Hz. When sending a 120 Hz signal there is no nearest neighbour upscaling.

Update 06/12/2018: A note for Xbox One X and Xbox One S owners: 1080p @ 120 Hz from the Xbox is only supported on this TV when the Xbox's connection type is changed from Auto-detect (Recommended) to HDMI: (Xbox > Settings > Display & sound > Video fidelity & overscan > Display > Connection > HDMI). Unfortunately in this mode 4k, HDR, 50 Hz and 24 Hz aren't possible, so this mode is only recommended when the higher refresh rate of 120 Hz is more important to you than these other features.

Update 06/18/2018: Correction, 24 Hz and 50 Hz are in fact possible with the Xbox's connection type set to HDMI.

Input Photos
Total Inputs
HDMI : 4
USB : 3
Digital Optical Audio Out : 1
Analog Audio Out 3.5mm : 1
Analog Audio Out RCA : 0
Component In : 1 (shared)
Composite In : 1 (shared)
Tuner (Cable/Ant) : 1
Ethernet : 1
DisplayPort : 0
IR In : 1
SD/SDHC : 0

The only combined composite/component input is located on the rear of the TV. The second composite input that was found on the side of the X850E has been removed.

Inputs Specifications
HDR10
:
Yes
HDR10+
:
No
Dolby Vision
:
No
HLG
:
Yes
3D
:
No
HDMI 2.0 Full Bandwidth
:
Yes (HDMI 2,3)
HDMI 2.1
:
No
CEC : Yes
HDCP 2.2 : Yes (HDMI 1,2,3,4)
USB 3.0
:
Yes (1)
Variable Analog Audio Out : Yes
Wi-Fi Support : Yes (2.4 GHz, 5 GHz)
6.2 Frequency Response
Low-Frequency Extension
:
119.87 Hz
Std. Dev. @ 70
:
3.75 dB
Std. Dev. @ 80
:
4.07 dB
Std. Dev. @ Max
:
6.21 dB
Max
:
88.0 dB SPL
Dynamic Range Compression
:
3.77 dB

The X850F has a mediocre frequency response. The LFE (low-frequency extension) of 120Hz is inadequate for creating the punch and rumble common to bass-heavy music and movie sound effects. The frequency response above the TV's LFE is quite well-balanced, but since it doesn't have a self-calibrating system, it wasn't able to remove our lab's room modes. This shows as a build-up of energy in the high-bass/low-mid region. On the upside, the TV does get loud enough for most use cases, and doesn't produce too much pumping and compression artifacts under heavy loads.

5.6 Distortion
Weighted THD @ 80