No, the UI controls do not use DirectX. The controls all use standard Windows GDI for drawing. Most graphics cards have direct hardware support for GDI operations. In addition to GDI, the 3D graph uses OpenGL; it will perform better if the graphics card has direct support for OpenGL. To realize this performance benefit, you have to set the CNiGraph3D::Use3DHardwareAcceleration to true (you can do this from the property pages as well).