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LG OLED48CX9LB in the test: The OLED television that wants to be a 120 Hz monitor

Last updated on March 9, 2021

LG’s 48-inch 48CX9LB just fits on the table. With HDMI 2.1 and fast OLED , it turns out to be a surprisingly good monitor.

The LG OLED48CX9LB just fits on the table. (Image: Oliver Nickel /

The Xbox Series X and Playstation 5 are about to go on sale. Both consoles will support 4K resolutions at a maximum of 120 Hz. This also applies to Nvidia’s Ampere graphics cards, which are slowly finding their way into home PCs. HDMI 2.1 makes this possible.

But what about suitable screens? If we look at traditional manufacturers, we won’t find anything until next year. Perhaps that is one reason why LG is prominently promoting the 48-inch OLED TV 48CX9LB as a display for games. In our test of the OLED TV, we examined whether this promise can be kept. We think: There are many approaches in favor of it. However, there are some flaws, some of which stem from the TV origin of the device.

When we unpack the screen, we immediately notice that a 48-inch television is actually too big for a small desk. As a pure TV for the living room, however, we consider it a little too small. So it’s good that LG also offers the model in 55 to 77 inches – for more money. The built-in power cord and a total of four HDMI 2.1 ports are on the back of the monitor, as well as a network cable (RJ-45) and cable or satellite connection. There are also three USB 2.0 ports and a PCMCIA card slot. Sound systems are connected using a headphone jack or an optical Toslink cable.

component Data
Display 48 inch OLED (3840 x 2160 pixels @ 120 Hz, 320 cd / m², 10 bit HDR400)
connections 4x HDMI (1x eARC), 3x USB-A 2.0, 1x RJ-45, 1x S / PDIF, 1x 3.5 mm jack, 1x PCMCIA slot, 2x satellite socket, 1x cable antenna socket
Additional functions AMD Freesync Premium, Nvidia G-Sync-compatible, Motion Blur Reduction, Ultra Low Latency Mode
Electricity demand 175 to 220 watts at maximum brightness
Dimensions 107.1 x 65.0 x 25.1 cm
LG OLED48CX9LB – overview

It’s a shame that LG doesn’t sell 43-inch versions or even smaller models. We later find out that OLED is in some cases superior to other technologies such as IPS (In-Plane Switching), VA (Vertical Alignment) and TN (Twisted Nematic), especially in games. On the other hand, it is economically understandable if the company does not want to cannibalize its own monitor division with televisions.

For our test we use a Geforce RTX 3070 from Nvidia (test) . The Ampere GPU should be able to handle most games in 4K and at 120 Hz frame rate. Also important: like the LG TV, the GPU supports HDMI 2.1. So we can enjoy the picture in 120 Hz and in native 3840 x 2160 pixels. However, the television also reports a supported resolution of 4,096 x 2,160 pixels, which no longer fully corresponds to the classic 16: 9 format. 120 Hz and 10 bit color depth are possible in both resolutions.

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The 48CX9LB can be installed using the supplied rigid stand or a Vesa mount. We think: When viewed from the front, the thin display bezels and the chic design come into their own. The television also stands solidly and firmly on its fairly large base. One point of criticism, however, is the large rear part of the base, which protrudes several centimeters. The result is that we cannot place the gaming monitor replacement completely on the edge of the table. This increases the lack of space on the worktop.

Windows 10 on the TV (Image: Oliver Nickel /

Not quite plug and play

After commissioning, we notice once again how colorful and rich in contrast OLED panels are. The LG monitor is no exception. The high black levels of OLED technology come into their own when watching films and series. We can see that in the Netflix series Altered Carbon, which is filmed quite dark and rich in contrast and accentuates colors through neon-colored elements in cyberpunk style.

LG OLED48CX9LB 121 cm (48 inch) OLED TV (4K, Dual Triple Tuner (DVB-T2 / T, -C, -S2 / S), Dolby Vision, Dolby Atmos, Cinema HDR, 100 Hz, Smart TV) [model year 2020 ] [Energy class A]

However, if we want to use the TV as a monitor, we have to make some settings. The device is therefore not entirely plug and play. First of all, it is important to switch off various automatic color and brightness controls in the TV’s WebOS menu. It is extremely distracting when the image display changes visibly during work.

Even if we switched off functions such as brightness AI, dynamic contrast and the automatic brightness control, our test pattern behaves a bit strange in connection with Windows 10. For example, the display darkens significantly with large, homogeneous white surfaces. Even when we open the start menu, for example, a difference in brightness and color intensity is already noticeable. This always applies when still images are displayed. In games or when watching series, automatic darkening is barely or not at all noticeable.

The OLED TV shines in full brightness, … (Image: Oliver Nickel /

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Even after trying things out for a long time, we couldn’t find out why. LG may be installing an automatic burn-in protection that cannot be changed by the people sitting in front of it. This function is built into at least some other LG products.

We can understand the burn-in protection, but still find it a shame that there is no way to switch it off or at least change it without additional tools. A detour is to use the Filmmaker mode instead of the more responsive game mode. This does not seem to use the automatic darkening, presumably in order not to distort colors when creating photos and videos. However, we then lose the advantage of low input latency. The mouse and keyboard controls feel rather spongy there. Fast games are unthinkable for us.

Automatic dimming makes professional display calibration difficult. We could also find the problem in our test when we measured the device for color accuracy and brightness. Setting a fixed individual illumination here is not easy. Instead, we ran the Displaycal software in front of a black background image in order to achieve the highest possible level of illumination.

The brightness of the panel is sufficiently good, if not outstanding. OLED is really convincing, especially in games.

its own website . The manufacturer presumably operated the television on low brightness levels, which makes the picture less clear, especially in dark game scenes.

LG OLED48CX9LB 121 cm (48 inch) OLED TV (4K, Dual Triple Tuner (DVB-T2 / T, -C, -S2 / S), Dolby Vision, Dolby Atmos, Cinema HDR, 100 Hz, Smart TV) [model year 2020 ] [Energy class A]

WebOS with partly useless settings

In our opinion, LG’s WebOS is one of the better smart TV operating systems thanks to the remote controls with mouse cursors. Important applications such as Youtube, Netflix and Amazon Prime Video are clearly arranged in a menu ribbon. The OS always reacts quickly enough to inputs and we can also find a large selection of programs for the television in the LG store.

Settings menu of the television (Image: Oliver Nickel /

It is a bit of a shame that LG, like Samsung, collects various location data and other information from customers by default. In some cases this should help to improve your own services like Thinq AI. These can automatically adjust the brightness or the sound profile of the television. However, we think this is unnecessary, we can simply adjust the picture ourselves. We also ask ourselves which person should ever use twelve different preset image profiles. Advanced learners set their own picture and beginners are overwhelmed by the large selection.

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So it’s good that we can simply switch off data collection. If we use the TV as a monitor, we can save ourselves the connection via WLAN or Ethernet cable to the local network. The setup of the TV works without it.

various retailers from around 1,500 euros. Larger versions cost more money accordingly. There is also a model in 55, 65 and 77 inches available. These are respectively 1,600, 2,000 and 4,300 euros.


As a pure television, at least the 48-inch version of the CX9LB is a bit too small, at least if it is primarily used for a great home cinema experience in the living room. Perhaps that’s why LG is also promoting the television as a monitor replacement.

It definitely has the specifications: With 120 Hz, Freesync, G-Sync and a special game mode with a very low input delay, it is actually a pleasure to play our favorite games on it.

Another advantage is the extremely fast OLED panel. Even with rapid movements in Counter-Strike: Global Offensive, we can always recognize opponents and objects very well. Streaks or ghosting are hardly noticeable.

The large screen diagonal and the resolution of 3840 x 2160 pixels is an advantage in strategy games that support high zoom levels – such as Age of Empires 2 – Definitive Edition or Civilization 6. Since the television supports HDMI 2.1, it should also be of interest to people who want to buy one of the upcoming game consoles.

The display bezels are very narrow. (Image: Oliver Nickel /

A bit of a shame: Despite switching off various automatic brightness functions, the display darkens by itself when we use it with Windows 10. This can be observed especially when working in documents or while browsing the web. In games, however, this is less noticeable.

LG OLED48CX9LB 121 cm (48 inch) OLED TV (4K, Dual Triple Tuner (DVB-T2 / T, -C, -S2 / S), Dolby Vision, Dolby Atmos, Cinema HDR, 100 Hz, Smart TV) [model year 2020 ] [Energy class A]

The maximum brightness of 402 cd / m² with HDR switched on is not necessarily outstanding either. Therefore we can ignore the better color depth even if it is supported.

The 48-inch LG monitor is sure to be particularly popular as a dedicated gaming screen for the Playstation 5 or Xbox Series X. The fast OLED panel also makes us want to be able to acquire it in formats that are more manageable for the desk. Maybe we don’t have to wait too long for it.