Profiler suggests that the min/max functions for x/y/z of the Toolpath object were the main bottleneck. They iterate through all the points in each path every time they are accessed. These values are now cached which provides a huge speed boost. Originally I thought the problem was the opengl drawing code so I created a new code path that converts moves into an arrays of vertices and indices. The vertices array particularly is stored in video memory. While faster, I don't think it is all that much faster.

Whitham D. Reeve II