The Hisense U8K has extremely low input lag, resulting in a responsive gaming or desktop experience. Unlike the TCL QM8/QM850G QLED, the TV’s input lag decreases accordingly as the refresh rate increases. The TV outputs proper chroma 4:4:4 when in Game Mode, so you can have clear text and the fastest possible input lag when using this TV as a PC monitor.
The TV can’t do proper 1080p @ 240Hz when VRR is enabled; it instead locks itself to 72Hz with resolution halving, with a measured input lag of 36.1ms. With VRR disabled, the TV does proper 1080p @ 240Hz, with a measured input lag of 3.3ms.
Note that these numbers were measured with the ‘High Refresh Rate’ mode disabled except at 1080p @ 240Hz, as it locks itself to ‘On’ at that refresh rate. Enabling the setting at refresh rates lower than 240Hz increases input lag by about 6ms.