Currently, XML Documentation for members (i.e. the /// comments in C# source files) is parsed from the generated *.xml files after a build. This parsing runs in the BL thread for each assembly reload and can take a while (especially for huge files like mscorlib.xml).

In Bolt 2, XML Documentation will be parsed only during Full Extractions and stored in the Extracted.bin binary file alongside unit options. This way, loading the documentation in to memory will be a much faster operation.