It's known information, you can't get good CPD with 15.12, need OCL from 14.x. This substitution works well on Windows 7 and Linux, but may not properly works on Windows 10.

Here is collection of OCL part from different drivers:
http://cryptomining-blog.com/tag/amd-opencl/
Direct link: http://cryptomining-blog.com/wp-content/download/amd-opencl-driver-versions.zip