Release26 seems to be a tiny bit slower than 25 for me (GTX970, X11).
I tested on the 980 and the 970. The launch configuration was way off. the new blake code needed different launchparameters. I modified a bit, and booom 150KHASH more (x11)
will test some more and submit to github. The standard clocked 980 is now hashing at 9MHASH.