Helix problem?

 From:  Michael Gibson
3312.2 In reply to 3312.1 
Hi Nick, it's the apparent intersection snap kicking in - when a helix like that is projected down to a plane for generating the apparent intersection snap it produces a flattened curve that loops around over and over on top of itself and that tends to cause the intersection mechanism to do a lot of extra work.

Here's a couple of previous posts about it:

The problem should go away if you disable apparent intersection snaps.

- Michael