Extrusions display problem

I have a problem with the display of extrusions as you can see on the image…the curve is smooth but the render comes out segmented…
I tried several things but nothings helped…

does anyone have any idea?

Did you try the mesh settings?

Yes I changed the mesh settings in the document properties and the segmentation was gone but everything got really slow…

Looks like your May 2016 Intel driver only supports OpenGL 3.1. Are you using Rhino 5 or 6?

I’m using Rhino 5

But as you can see on the right, there’s no problem when I draw a new extrusion…