You are running your monitors at different refresh rates. There is a long-standing bug in Windows that causes lag/stutter/skip due to the desktop compositor process not dealing with multiple refresh rates with hardware-accelerated programs. Set both monitors to run at 60hz.02:34:44.904: output 0: pos={0, 0}, size={1920, 1080}, attached=true, refresh=75, name=LG FULL HD
02:34:44.905: output 1: pos={-1360, 0}, size={1360, 768}, attached=true, refresh=60, name=