GL Points slow on NV40 with 8XS anti-aliasing enabled


Does anyone know why drawing gl points is so slow on NV40 hardware with 8xs (4 sub, 2 super samples) anti-aliasing enabled.

When I render 8000 gl points with 4X antialiasing i get around 1200 fps. With 8xS antialiasing enabled i get only 60fps!

Its strange as I can render that many billboarded quads with 8xS anti-aliasing enabled much faster (around 600 fps).

Is it a driver bug? I am using the latest windows drivers.