While i was rendering some images, i noticed that
A nurbs cylinder does render a lot better dan a normal cylinder,
Just keep it a nurbs and dont make a mesh of it.
If you need a closed top of this cylinder type then just click extrude then dont do anything and do anther extrude, then scale second extruded those top points to zero, when the top is closed press ctrl + and then move both extrusions a tiny amount upwarts.
These cylinders will never show up the faces of a shape, so are real highres and because of their nature thy render fast while working with them.
I am only left puzled why nurbs are not seen that often.