Hi Uwe.

We turned of antialiasing and that improved the performance. We had bad X11 configuration on one of the machines, but that should be fixed.

In addition to the curves, we have a dotted grid on our canvas. The canvas doesn't have any gradients, it's just black.

We've tried the raster graphicssystem, without any significant change in performance.

We only have a couple of points on each curve outside the visible area.

Thanks for your help.

Gerhard