title: Big integers in C#
body: <p>Currently I am <a href="http://msdn.microsoft.com/en-us/magazine/cc163696.aspx" rel="noreferrer">borrowing <code>java.math.BigInteger</code> from the J# libraries as described here</a>. Having never used a library for working with large integers before, this seems slow, on the order of 10 times slower, even for <code>ulong</code> length numbers. Does anyone have any better (preferably free) libraries, or is this level of performance normal?</p>