Update 05/02/2019: We've retested the input lag of the LG C9 with the firmware update 03.50.31. The input lag measurements in SDR game and PC modes have decreased.

Update 05/09/2019: Text clarifications added.

Update 05/17/2019: We've retested the input lag on the same firmware (03.50.31) and found the 4k @ 60Hz + HDR input lag is in the same ballpark as the other resolutions (around 13ms). We don't know why our previous measurements were higher, as we did confirm them twice. We've also updated the 1440p @ 60Hz input lag with this latest firmware.

Update 06/01/2020: We've retested the input lag with G-SYNC enabled using the latest firmware (04.70.05) and the score has been adjusted accordingly. Unfortunately, we were still unable to get a 4k @ 120Hz signal, as we needed a HDMI 2.1 source, and we can't retest the TV since we've sold it. The tests were performed on a PC equipped with an NVIDIA RTX 2070 graphics card.

The LG C9 has outstanding low SDR input lag in 'Game' mode. In 'PC' mode, the input lag is higher than the C8, which is somewhat strange. With the latest firmware (05.30.31) we measured a higher input lag with 4k @ 60Hz + HDR signals. This is fine for most people, but may be disappointing for fast-paced HDR games. This is strange, and we expect it to be reduced in a future firmware update. New on the LG C9 is support for Auto Low Latency Mode.