Hi Max, well a 100 MB of curves is probably quite a whole lot of them. It takes quite a bit of work to draw curves since they are refined on demand to look nice and smooth at the current zoom level. That takes a lot of calculation and lots of calculation tends to take time...

But normally if you hide everything it should speed up the display... If it's possible for you to send me the file where you are seeing the slowdown happen, please send that to me at moi@moi3d.com (for such a large file you'll need to send me a link to a file sharing service like dropbox or something like that, not as a direct file attachment), and I'll take a look at it when I return from vacation to see if I can improve any bottlenecks.

Thanks,
- Michael