Andrucrypt, running 0.9.17 for extended time period leads me to the following observation.  For whatever reason, the hashing for this miner when it has been running continously for many hours to days seems to slow down due to increased rate of rejected shares.  Maybe it is a memory leak type issue, I dunno.

I do observe that the first hour or two has very low rejected shares rate, and this observation is consistent when you close and reopen the miner.  So for now, what works best for me is to run a .bat file that runs the miner for 2 to 3 hours, shut it down, and reopen it again for optimal performance.

Don't know how you can easily troubleshoot this type of issue but I am at least pointing it out.  I do think your miner outperforms both ccminer and the openCl miner in terms of net raw performance at the pool side, but this rejected shares issue is inhibiting optimal overall speed.