Please pay attention to IPP documentation. To use static linkage you need both ippExmerged and ippxmerged libraries, where libraries with 'e' letter are static dispatcher libraries and 'x' stands for any particular IPP domain.
The slowdown at static libraries linkage is caused by small footprint technology we use in IP static libraries to minimize the final executable size. For this purpose we split each function in separate compilation unit. As a result, your final executable will only contain those functions which used in your application.