As a test, can you exclude the smaller monitor, and try with just the two which have identical resolutions? I am testing with 2 x FHD (1920x1080), also using Intel integrated graphics and the display of the menu fonts is sharp. In the Intel HD Graphics Control Panel, Display->General Settings, make sure the resolution is set to the native resolution of the monitors (with identical resolutions) and under Scaling, select “Maintain Aspect Ratio”. Does that help?