For what it's worth, we have a number of rigs using this miner for the past couple of weeks or so and have not had any significant drop in hashrate over time. All of the rigs are on Windows 10 Pro with page file set to the total amount of Vram plus a little bit extra. 80% power limit and a moderate core OC (+100-175 depending on the model of GPU). --- 388.71 drivers, vga drivers only installed, no audio, 3dsurround, geforce experience etc installed.
Yes, I managed to get this to run very consistently with my FE GTX 1080, but hashrate dropped after some period of time on both my Asus ROG Strix 1080 and my one "real" rig of 6x GTX 1060.
Worse is that I just mined TZC for 4.5 hour with my 6x 1060 rig on the official pool (which finds blocks every few minutes) and got credited for 15.8 coins instead of the expected 18.4 - that's about 15% less, meaning my effective hashrate was more like 3700 kH/s rather than the 4300 kH/s claimed by the program. In fact, that makes the effective hashrate worse than ccminer-klaust 8.19...
I'm not sure what's going on here, but it sure looks funky from my perspective.