What is the reason behind this huge Performance difference in .Net 4

Question

I was just doing some research on RedBlack Tree. I knew that SortedSet class in .Net 4.0 uses RedBlack tree. So I took that part out as is using Reflector and created a RedBlack

Answer 1

1. reverse the order of the tests and repeat the measurement.
2. randomize your data. Sorted sets behave strangely when you insert pre-sorted data.