When ever my rig have been running for a day or two, the hashing rate drops.
Just checked my hash rate and it was 2200 sol/s - 2300 sol/s - restarted and back to 2600-2700 sol/s.
Isn´t that a bit strange?
6x1070 evga black edition 8 gb
8 gb ram
Carbon Pro mobo and SSD