Very useful and informative technical notes on Using Intel IPP with OpenCV are available on IPP Knowledge Base. In this notes test cases are provided to demonstrate following details.
Use Intel IPP library and OpenCV library independently
Integrate Intel IPP library into OpenCV library and use OpenCV with built-in Intel IPP
Compare OpenCV, OpenCV with built-in Intel IPP, and Intel IPP
Link to technical notes: http://software.intel.com/en-us/articles/using-intel-ipp-with-opencv/