Anti Aliasing

Which antialiasing algorithm OpenGL uses?

It’s depends on the videocard.

glEnable(GL_POLYGON_SMOOTH);
glHint(GL_POLYGON_SMOOTH_HINT, GL_FASTEST);

If you use
glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);

It must be slowest. It want the modern hardware video card.

A better, and more widely used AA method is the GL_ARB_multisample extension