LG 48 CX OLED Monitor Review

Tested using Methodology v1.1
Reviewed Aug 11, 2020 at 08:01 am
LG 48 CX OLED Picture
8.3
Mixed Usage
8.1
Office
8.6
Gaming
8.4
Multimedia
8.1
Media Creation
8.7
HDR Gaming
Size 48"
Resolution 3840x2160
Max Refresh Rate
120 Hz
Pixel Type
OLED
Variable Refresh Rate
FreeSync

We bought and tested the LG 48 CX OLED as a computer monitor, and even though this is meant to be a TV, it offers impressive overall performance as a monitor. Its 4k resolution delivers an exceptionally clear image, the OLED technology displays perfect blacks, and it has very wide viewing angles. It's an excellent choice for gaming because it has native FreeSync variable refresh rate (VRR) support and it's G-SYNC compatible, the response time is near-instant, and it has a low input lag. Sadly, it doesn't get very bright because of its aggressive automatic brightness limiter (ABL), but if you want to place it in a bright room, it has outstanding reflection handling. It's a really well-built TV with a sleek design, but unlike most monitors, its stand doesn't allow for any adjustments.

Like any OLED, it has the risk of permanent burn-in. This could be an issue with constant static displays like a computer's interface, but if you use a screensaver when you're not using it or if you also use it for watching varied content, you may avoid, or at least reduce, the risk.

Our Verdict

8.3 Mixed Usage

The LG 48 CX OLED is an impressive overall TV to use as a computer monitor. It's a great choice for any type of use, and it's excellent for gaming. It has a 120Hz refresh rate, native FreeSync support, and a near-instant response time. It has excellent viewing angles, great if you want to use it in an office setting or sit close to the screen. Sadly, the screen doesn't get bright enough to combat glare, but it has outstanding reflection handling. Lastly, it's a great choice for watching movies since it has an infinite contrast ratio.

Note: This isn't comparable to the 8.8 score the LG CX received in our TV review because of different scoring methods between monitors and TVs.

Pros
  • Displays perfect blacks.
  • Extremely wide viewing angles.
  • FreeSync VRR support.
  • Near-instant response time.
  • Outstanding reflection handling.
8.1 Office

The LG 48 CX OLED is great for office use. It has a big 48 inch screen and a 4k resolution, great for opening multiple windows at once. Sadly, its stand doesn't allow for any type of adjustment and the screen doesn't get very bright. On the upside, it has outstanding reflection handling and it has extremely wide viewing angles.

Pros
  • Extremely wide viewing angles.
  • Outstanding reflection handling.
  • Outstanding gray uniformity.
8.6 Gaming

Excellent choice for gaming. The LG 48 CX OLED has FreeSync VRR support and owners of NVIDIA graphics cards can take advantage of the G-SYNC compatibility. It has a 120Hz refresh rate, a near-instant response time, and a low input lag, although it's not as low as other monitors. It's an ideal choice for gaming in the dark as it's able to individually turn off pixels, producing perfect blacks.

Note: This isn't comparable to the 9.1 score the LG CX received in the TV review because of different scoring methods between monitors and TVs.

Pros
  • Displays perfect blacks.
  • FreeSync VRR support.
  • Near-instant response time.
  • Low input lag.
Cons
8.4 Multimedia

The LG 48 CX OLED is impressive for watching movies and videos. It has a high 4k resolution, it has an infinite contrast ratio and perfect black uniformity, and it handles reflections extremely well. It's also a great choice for watching videos with friends since it has very wide viewing angles. Lastly, it has a built-in smart operating system, so you get a ton of apps available to download without even turning on your PC.

Pros
  • Displays perfect blacks.
  • Extremely wide viewing angles.
  • Outstanding reflection handling.
8.1 Media Creation

Great for content creators. The LG 48 CX OLED has a large 48 inch screen and a high 4k resolution, great for multitasking. It has very wide viewing angles and it's a great choice to use in bright rooms because it has outstanding reflection handling. Sadly, it has limited coverage of the Adobe RGB color space used in photo editing and it has mediocre out-of-the-box color accuracy. On the upside, it has an infinite contrast ratio, producing perfect blacks.

Pros
  • Displays perfect blacks.
  • Extremely wide viewing angles.
  • Outstanding reflection handling.
8.7 HDR Gaming

The LG 48 CX OLED is an excellent choice for HDR gaming. It has native FreeSync VRR support, it's G-SYNC compatible, and it has a 120Hz refresh rate. The response time is near-instant and it has a low input lag. It supports both Dolby Vision and HDR10 and it displays a great wide color gamut for HDR content. It also gets bright enough to make small highlights pop in HDR the way they're supposed to.

Note: This isn't comparable to the 8.8 score the LG CX received in the TV review because of different scoring methods between monitors and TVs.

Pros
  • Displays perfect blacks.
  • FreeSync VRR support.
  • Near-instant response time.
  • Gets bright enough to make small highlights pop in HDR.
Cons
  • 8.3 Mixed Usage
  • 8.1 Office
  • 8.6 Gaming
  • 8.4 Multimedia
  • 8.1 Media Creation
  • 8.7 HDR Gaming
  1. Update 9/22/2020: Tested an issue when displaying chroma 4:4:4.

Video

Test Results

perceptual testing image
Design
Design
Style
Curved No
Curve Radius Not Curved
Weight (without stand)
33.5 lbs (15.2 kg)
Weight (with stand)
42.3 lbs (19.2 kg)

The LG 48 CX OLED has a premium design and because it's a TV, its stand is different than most monitors, allowing it to sit close to the table. It's made from both metal and plastic and it has a silver finish to it.

Design
Stand
Width
32.9" (83.6 cm)
Depth
10.0" (25.4 cm)

The front of the stand is metal and the back is plastic, and it supports the LG 48 CX OLED very well. The stand has a wide footprint, so you need a big table to place it on. It also sticks out a bit from the screen, so you may need some extra space in front to put your keyboard and mouse.

0
Design
Ergonomics
Height Adjustment
N/A
Switch Portrait/Landscape No
Swivel Range No swivel
Tilt Range No Tilt

The stand doesn't allow for any type of adjustment.

Design
Back
Wall Mount VESA 300x200

The back of the LG 48 CX OLED has a premium look to it. The top half is made from a textured metal, and the bottom half where the inputs are is solid plastic. It can be VESA-mounted, but you need to manually take off the stand as it doesn't have a quick-release button like some monitors. Lastly, cable management is done through the stand.

Design
Borders
Borders
0.3" (0.9 cm)

The borders of the LG 48 CX OLED are thin and aren't distracting.

Design
Thickness
Thickness (with stand)
8.0" (20.2 cm)
Thickness (without stand)
1.8" (4.5 cm)

The LG 48 CX OLED is fairly thin on its own and doesn't stick out much if you wall-mount it. However, it gets much thicker with the stand attached.

9.0
Design
Build Quality

Outstanding build quality. The LG 48 CX OLED is mainly made out of metal and the back of the stand and the panel holding the inputs are both made out of solid plastic. The entire TV is solid and there isn't much flex throughout.

Picture Quality
10
Picture Quality
Contrast
Native Contrast
Inf : 1
Contrast With Local Dimming
N/A

The LG 48 CX OLED is able to individually turn off pixels, producing an infinite contrast ratio.

10
Picture Quality
Local Dimming
Local Dimming
No
Backlight
No Backlight

The LG 48 CX OLED doesn't have a local dimming feature since it doesn't have a backlight and can turn individual pixels off. Bright objects and subtitles are displayed perfectly.

6.9
Picture Quality
SDR Peak Brightness
SDR Real Scene
260 cd/m²
SDR Peak 2% Window
262 cd/m²
SDR Peak 10% Window
261 cd/m²
SDR Peak 25% Window
260 cd/m²
SDR Peak 50% Window
260 cd/m²
SDR Peak 100% Window
167 cd/m²
SDR Sustained 2% Window
249 cd/m²
SDR Sustained 10% Window
249 cd/m²
SDR Sustained 25% Window
247 cd/m²
SDR Sustained 50% Window
247 cd/m²
SDR Sustained 100% Window
160 cd/m²
SDR ABL
0.031

The LG 48 CX OLED has just okay peak brightness, similar to most OLED TVs. Its automatic brightness limiter (ABL) is slightly aggressive, so the brightness significantly drops at the 100% window. This means that a white webpage or document isn't bright enough to combat glare. This doesn't get as bright as the LG CX OLED TV because this was tested in 'PC' mode, which is what we expect most people to have it in while using it as a monitor. If you want to use it for gaming or watching movies, you can use the other pictures modes and the TV will be brighter.

We measured the peak brightness after calibration in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC', which disables some picture settings, including Peak Brightness. Outside of 'PC' mode in the 'Expert (Dark Room)' Picture Mode with Peak Brightness set to 'High', most scenes are between 248 to 343 cd/m², and we got 178 cd/m² in the 100% sustained window test and 273 cd/m² in a real scene.

If you want the brightest image possible and don't care so much about image accuracy, we were able to 369 cd/m² in the 10% peak window test in 'Expert (Dark Room)' Picture Mode outside of 'PC' mode before calibration.

7.2
Picture Quality
HDR Peak Brightness
HDR Real Scene
571 cd/m²
HDR Peak 2% Window
725 cd/m²
HDR Peak 10% Window
724 cd/m²
HDR Peak 25% Window
394 cd/m²
HDR Peak 50% Window
242 cd/m²
HDR Peak 100% Window
129 cd/m²
HDR Sustained 2% Window
685 cd/m²
HDR Sustained 10% Window
689 cd/m²
HDR Sustained 25% Window
372 cd/m²
HDR Sustained 50% Window
231 cd/m²
HDR Sustained 100% Window
124 cd/m²
HDR ABL
0.109

Decent HDR peak brightness. The LG 48 CX OLED gets bright enough to make small highlights pop in HDR. However, it quickly loses its brightness as larger, bright areas cover the screen due to the very aggressive ABL.

We measured the brightness with OLED Light at its max and Peak Brightness set to 'High' in 'Game HDR' Picture Mode, which is what we expect most people to use while using this as a PC monitor to get the lowest input lag possible. We got the brightest image possible with these settings as seen in the 2% peak window test. The 'Cinema' Picture Mode has a higher peak brightness, as seen in the TV review.

8.5
Picture Quality
Horizontal Viewing Angle
Color Washout From Left
52 °
Color Washout From Right
62 °
Color Shift From Left
26 °
Color Shift From Right
28 °
Brightness Loss From Left
61 °
Brightness Loss From Right
61 °
Black Level Raise From Left
70 °
Black Level Raise From Right
70 °
Gamma Shift From Left
56 °
Gamma Shift From Right
57 °

Like most OLED TVs, the LG 48 CX OLED has a very wide horizontal viewing angle. The image remains accurate when viewing from the side, which is ideal for meeting rooms.

9.0
Picture Quality
Vertical Viewing Angle
Color Washout From Below
70 °
Color Washout From Above
70 °
Color Shift From Below
26 °
Color Shift From Above
28 °
Brightness Loss From Below
69 °
Brightness Loss From Above
68 °
Black Level Raise From Below
70 °
Black Level Raise From Above
70 °
Gamma Shift From Below
59 °
Gamma Shift From Above
59 °

The LG 48 CX OLED has an outstanding vertical viewing angle, which is expected from an OLED TV. The image remains accurate even if you sit close to the screen.

9.1
Picture Quality
Gray Uniformity
50% Std. Dev.
1.228 %
50% DSE
0.095 %
5% Std. Dev.
0.470 %
5% DSE
0.071 %

The LG 48 CX OLED has remarkable gray uniformity. There aren't many visible uniformity issues throughout, and in near-dark scenes, there's some minor vertical banding, which is common with OLED displays. The gray uniformity is better than the LG CX OLED TV we reviewed, but this is something that varies between units.

10
Picture Quality
Black Uniformity
Native Std. Dev.
0.109 %
Std. Dev. w/ L.D.
N/A

Since the LG 48 CX OLED is able to individually turn off pixels, it has perfect black uniformity.

6.1
Picture Quality
Pre Calibration
Picture Mode
Expert (Dark Room)
Luminance
103 cd/m²
Luminance Settings
33
Contrast Setting
85
RGB Controls
0-0-0
Gamma Setting
2.2
Color Temperature
5840 K
White Balance dE
4.72
Color dE
3.53
Gamma
2.28

The LG 48 CX OLED has mediocre out-of-the-box color accuracy. Most colors are slightly inaccurate and the color temperature is warm, giving the image a red/yellow tint. White balance is off, which affects the shades of gray, and gamma doesn't follow the target curve well, so most scenes are too dark, except for really bright scenes, which are over-brightened. We measured this in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC'.

Note that the LG CX OLED has a much higher color accuracy before calibration, and this is partially due to the different color targets in testing between monitors and TVs. Color temperature is also different between this 48 inch model and the 55 inch TV we tested, but this can vary between units.

9.3
Picture Quality
Post Calibration
Picture Mode
Expert (Dark Room)
Luminance
102 cd/m²
Luminance Settings
28
Contrast Setting
91
RGB Controls
High ((-9)-5-17), Low ((-1)-(-1)-(-1))
Gamma Setting
2.2
Color Temperature
6438 K
White Balance dE
0.71
Color dE
1.21
Gamma
2.18

The LG 48 CX OLED has an amazing color accuracy after calibration. Any remaining inaccuracies aren't visible without the aid of a colorimeter, and gamma follows the curve much better, except bright scenes are still slightly over-brightened. We measured this in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC'.

You can download our ICC profile calibration here. This is provided for reference only and shouldn't be used, as the calibration values vary per individual unit even for the same model due to manufacturing tolerances.

8.4
Picture Quality
SDR Color Gamut
sRGB xy
94.6 %
Adobe RGB xy
73.8 %
sRGB Picture Mode
Expert (Dark Room)
Adobe RGB Picture Mode
Expert (Dark Room)

The LG 48 CX OLED has an impressive SDR color gamut, but not as good as most monitors. It covers almost all of the sRGB color space used in most content, but it has limited coverage of the Adobe RGB color space used in photo editing. We measured this in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC'.

8.9
Picture Quality
SDR Color Volume
sRGB In ICtCp
97.1 %
Adobe RGB In ICtCp
80.8 %
sRGB Picture Mode
Expert (Dark Room)
Adobe RGB Picture Mode
Expert (Dark Room)

The LG 48 CX OLED has an excellent SDR color volume. It displays dark, saturated colors really well due to its infinite contrast ratio. We measured this in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC'.

7.8
Picture Quality
HDR Color Gamut
Wide Color Gamut
Yes
DCI P3 xy
88.3 %
Rec. 2020 xy
68.5 %
DCI P3 Picture Mode
Game HDR
Rec. 2020 Picture Mode
Game HDR

Very good HDR color gamut. The LG 48 CX OLED has excellent coverage of the commonly-used DCI P3 color space, but the coverage of the Rec. 2020 color space is more limited. We measured this in the 'Game HDR' Picture Mode with the input label set to 'PC'.

Note that this TV appears to have less coverage of the DCI P3 color space compared to the 55 inch LG CX OLED we tested on our TV test bench. This is due to the way we calculate DCI P3 coverage. On TVs, we estimate the DCI P3 coverage based on the Rec. 2020 measurements, but on Monitors, we measure the actual coverage. The 68.5% Rec. 2020 measurement we took on the 48" CX corresponds to a 97% DCI P3 coverage if calculated as a TV, which is also what we calculated on the 55" CX.

7.1
Picture Quality
HDR Color Volume
DCI-P3 In ICtCp
80.7 %
Rec. 2020 In ICtCp
60.8 %
DCI P3 Picture Mode
Game HDR
Rec. 2020 Picture Mode
Game HDR

Decent HDR color volume. Once again, the LG 48 CX OLED displays deep colors well, but it struggles to display a wide range of colors at different luminance levels. We measured this in the 'Game HDR' Picture Mode with the input label set to 'PC'.

9.2
Picture Quality
Image Retention
IR After 0 Min Recovery
0.25 %
IR After 2 Min Recovery
0.06 %
IR After 4 Min Recovery
0.02 %
IR After 6 Min Recovery
0.00 %
IR After 8 Min Recovery
0.06 %
IR After 10 Min Recovery
0.02 %

Unlike the LG CX OLED, the LG 48 CX OLED has some image retention, even 10 minutes after displaying a high-contrast test image. We didn't experience any temporary image retention with the 55 inch we tested in the TV review, but this could vary between units.

Note that this is different from the permanent burn-in OLED TVs may experience. Read more about the long-term burn-in risk here.

9.0
Picture Quality
Gradient
Color Depth
10 Bit

The LG 48 CX OLED has remarkable gradient handling. There's some banding in dark red, green, and gray, but this shouldn't be noticeable with most content. We measured this in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC'.

Note that this scores higher than the 8.6 in the TV review because the gradient score is subjectively assigned in monitors.

9.9
Picture Quality
Color Bleed
Pixel Row Error
0.002 %
Pixel Column Error
0.009 %

The LG 48 CX OLED has some very minor color bleed when displaying large areas of uniform color, but it shouldn't be noticeable for most people.

9.2
Picture Quality
Reflections
Screen Finish
Glossy
Total Reflections
1.3 %
Indirect Reflections
0.1 %
Calculated Direct Reflections
1.2 %

The LG 48 CX OLED has outstanding reflection handling. Unlike most monitors that have a matte finish, this has a glossy finish that performs really well even in direct sunlight.

7.0
Picture Quality
Text Clarity
Sub-Pixel Layout
WBGR

Update 09/22/2020: We received reports of people noticing vertical red lines appearing when displaying yellow or green. We recreated this issue and updated the text; see below for details.

The LG 48 CX OLED has decent text clarity. Since this TV uses a WBGR sub-pixel layout with four sub-pixels, all four are never turned on at the same time, and you can see the alternative pixel photo here. Only the blue and white pixels are turned on with a white background, as seen here, which affects the way text is displayed. Enabling ClearType (top photo) slightly improves the clarity on the diagonal lines of the letters R and N, but at 100% scaling, it might still be difficult for some to see text. Below is a list of text clarity photos at 125, 150, and 300% scaling with and without ClearType enabled.

Scaling ClearType On ClearType Off
100% ClearType On ClearType Off
125% ClearType On ClearType Off
150% ClearType On ClearType Off
300% ClearType On ClearType Off

Although Windows recommends to use 300% scaling on a PC, text is just way too big to be used by most people.

We received reports of the TV displaying vertical red lines when there are solid areas of yellow and green. This happens when the TV is in 'PC' mode and displaying chroma 4:4:4. Even though putting it out of 'PC' mode to display 4:2:2 helps reduce the issue, it makes text more blurry. We still recommend leaving the TV in 'PC' mode to get clear text, but you may notice these red lines. You can see the photo here.

Motion
9.9
Motion
Response Time @ Max Refresh Rate
Best Overdrive Setting
No Overdrive
Rise / Fall Time
0.8 ms
Total Response Time
1.8 ms
Overshoot Error
0.8 %
Dark Rise / Fall Time
0.7 ms
Dark Total Response Time
3.7 ms
Dark Overshoot Error
3.5 %

Overdrive Setting Response Time Chart Response Time Tables Motion Blur Photo
No Overdrive Chart Table Photo

Like most OLED TVs, the LG 48 CX OLED has a near-instant response time. There's some overshoot in the darker transitions, but this shouldn't cause too many artifacts. Unlike most monitors, there isn't any overdrive setting. Note that we needed to put the TV in chroma 4:2:0 subsampling to achieve 4k at 120Hz, due to technological limitations.

We measured this in the 'Game' Picture Mode with the input label set to 'PC', and the pictures are taken in the 'Expert (Dark Room) Picture Mode. Since OLED TVs have a near-instant response time, we don't expect the picture mode to change the response time.

Even though this scores the same as the LG CX OLED TV review, the measurements aren't comparable between monitors and TVs. We calculate the response time and overshoot in different ways between the two.

10
Motion
Response Time @ 60Hz
Best Overdrive Setting
No Overdrive
Rise / Fall Time
0.8 ms
Total Response Time
1.9 ms
Overshoot Error
0.4 %
Dark Rise / Fall Time
0.7 ms
Dark Total Response Time
3.8 ms
Dark Overshoot Error
1.9 %

Overdrive Setting Response Time Chart Response Time Tables Motion Blur Photo
No Overdrive Chart Table Photo

The LG 48 CX OLED has an incredible response time at 60Hz. There's only some minor overshoot in the darker transitions again, but this doesn't cause much motion blur. Like with the response time at its max refresh rate, the measurements are taken in the 'Game' Picture Mode with the input label set to 'PC', but the pictures are from the 'Expert (Dark Room)' Picture Mode.

10
Motion
Image Flicker
Flicker-Free No
PWM Dimming Frequency
0 Hz

The LG 48 CX OLED doesn't use Pulse Width Modulation (PWM), but there's a slight dip in brightness every 8 ms, which coincides with the 120Hz refresh rate. Most people shouldn't notice this. Note that the scaling of the graph isn't the same as the graph in the TV review, so although it may seem there's more flicker on this unit, it's the same between the 48 inch and 55 inch units we reviewed.

8.9
Motion
Black Frame Insertion (BFI)
Black Frame Insertion (BFI)
Yes
BFI Maximum Frequency
120 Hz
BFI Minimum Frequency
60 Hz

The LG 48 CX OLED has a black frame insertion (BFI) feature to improve the appearance of motion. We measured this in the 'Expert (Dark Room)' Picture Mode with the input label set to 'PC' and TruMotion set to 'High'.

8.6
Motion
Refresh Rate
Native
120 Hz
Max Refresh Rate
120 Hz
Variable Refresh Rate
Yes
FreeSync
Yes
G-SYNC
Compatible (NVIDIA Certified)
VRR Maximum
120 Hz
VRR Minimum
40 Hz
VRR Supported Connectors HDMI

The LG 48 CX OLED has an excellent refresh rate of 120Hz. It has native FreeSync VRR support, which helps reduce screen tearing. It's certified by NVIDIA to be G-SYNC compatible, and unlike most G-SYNC compatible monitors, such as the LG 34GN850-B, G-SYNC works over an HDMI connection.

Inputs
8.6
Inputs
Input Lag
Native Resolution
10.7 ms
Native Resolution @ 60Hz
13.6 ms
Variable Refresh Rate
11.1 ms
Variable Refresh Rate @ 60Hz
15.2 ms
10 Bit HDR