3-D sketch in 2008

[Mindnumb]

I need some tips regarding 3-d sketch perormance and issues.
It seems something is "broken" in the way sw2008 handles 3-d sketch. First, performance is lacking. I am using The routing add in, and for every new release of sw since 2001+, the performance as gone down, but the latest one is straight out horrible.
Second, the sketch tend to enter overdefined state for no good reason. Typically I have drawn up a fully defined an working sketch, then, when adding a free standing line, with no reference to the existing elements in the scetch, the sketch turns red and over defined. The newly added line itself and its endpoints have no relations. Why is this happening?

Any help appreciated!

 

[packmen]

usually in my case when the 3D sketch turn red with no reason I found a solution looking for duplicated relation, sometimes you can add a relation in the sketch that works fine, but if you chance a dimension it turns red when it should not, is like putting a parallel in two vertical lines in a 2D sketch, it works, but is completely unnecessary.

hope it helps