Will using DriverWorks have an impact on the performance of my driver? Will it run faster if I write it using only the DDK?
DriverWorks was designed to give equal performance to the DDK.
According to the DriverWorks manual:
"DriverWorks' careful function inlining and attention to detail mean you can take advantage of the DriverWorks framework without any performance penalty. Of course, the entire C-level API of the DDK is also available if your driver requires it"
DriverWorks code is generally very close to what would be written using the DDK. The full source code for the DriverWorks libraries is provided so that you can know exactly which DDK functions your driver is calling. You can also always make changes to the libraries or add in DDK functions if you feel the DriverWorks library is too slow.