This example has poor performance on Firefox due to the way we currently implement <use>, which is by doing an anonymous clone of the content tree. Updates to the original cause a reclone, which if <use> is used lightly isn't a big problem, but as in your example you have a large number of cloned objects to be updated each frame it will cause problems.

It might be faster to do something like the following:

  root = document.getElementById("TurbineMapScratchPad");
  id = root.suspendRedraw(1000);
  ... loop through each <use> and assign them a transform ...
  root.unsuspendRedraw(id);