Users have problems with RTX 3080 in combination with LG OLED TVs

Users who combine a GeForce RTX 3080 via HDMI 2.1 with LG OLED TVs from 2019 and 2020 run into problems. Nvidia’s G-Sync implementation of variable refresh rate does not work and CX models switch to 4: 2: 2 subsampling at 4k120Hz.

The use of the G-Sync Compatible function on the RTX 3080 video card in combination with LG OLED TVs results in a black image. This can be seen in a YouTube video from Tech YES City. Users on reddit also report similar issues. The relevant LG TVs, such as those from the C9 and CX series, are advertised as G-Sync Compatible. That’s Nvidia’s name for the implementation of the HDMI 2.1 feature variable refresh rate. AMD calls this FreeSync.

With the LG CX-OLed TVs, this year’s models, gamers are unable to get 4k120Hz in the picture with 4: 4: 4 display without compression. The TVs will automatically switch to 4: 2: 2 sub-sampling. HDMI 2.1 in particular makes playback at that resolution and frame rate possible without compression, but with the CX TVs that is currently not possible, according to users. Users also report that on the Nvidia forum.

With LG C9 TVs from last year, users are able to display 4k120Hz with 4: 4: 4 color coding. Those TVs have an HDMI 2.1 connection with a bandwidth of 48Gbit / s, while the CX TVs have a 40Gbit / s connection. However, that shouldn’t make a difference. Also the lower bandwidth of the CX models is enough to display 4k120Hz 4: 4: 4 at 10bit color depth. Additionally, users report that the TVs also switch to 4: 2: 2 when using an 8bit color depth, requiring even less bandwidth.

Twitter user Sixi82 shows the difference in picture quality between 4: 4: 4 and 4: 2: 2 and also said to have tested several HDMI cables to rule out that they are causing the problems. Presumably the problems can be solved with firmware and driver updates. LG and Nvidia have not yet commented on the users’ findings.

Playback with 4: 2: 2 subsampling (left) and 4: 4: 4 playback without compression