you can build OpenCV better optimized for this machine (cmake variables CPU_BASELINE and CPU_DISPATCH) - read more here, by default we use SSSE3 as baseline
you can build only limited subset of a library (just opencv_core and opencv_imgproc for example), can compose it into a single opencv_world.dll binary, make it static or dynamic
you can choose different options for video backends, parallel_for backend, windows backends, OpenCL, OpenGL support and many others
build modules which are not provided in default distributions: opencv_viz, all CUDA modules, all opencv_contrib modules
replace subset of functionality with your own functions via HAL (read more here)
you can built accuracy and performance tests and check how good does your platform perform basic operations before experimenting with complex algorithms