Monitor revert 640x480 at lower resolution

[frfr23]

hello cru , i have a 75hz monitor 1920x1080 the problem is 75hz is feel lag and scaling is wrong, i fixed but not complete, what I do I change the resolution to 1366x768 and chose refresh rate 59.887 but appear horizontal lines only on a low resolution at 59.887hz, the second problem is when I chose 60hz that appear only from "display adapter properties" on any lower resolution 1600x900,1400x900, 800x600, etc is revert me to 640x480, and when i go back to 1920x1080 75hz is lag and scaling wrong and work and feel different only when i put at lower resolution 59.887hz and go back to 1920x1080.