My setting:

Rig 1;
MOBO1 : Gigabyte z97 Gaming 7 LGA 1150
CPU: Intel Celeron G3250 LGA 1150
RAM: 4GB (2600 MHz)
Windows 10

with -i 8
GPU's
3 x MSI AMD R9 390 8GB, 1081/1500 (speed with CM V12.1 = 390 H/s)
2 x XFX AMD R9 390X 8GB, 1112/1500 (speed with CM V12.1 = 410 H/s)
1 x ASUS AMD R9 390 8GB, 1091/1500 (speed with CM V12.1 = 395 H/s)

Rig 2:
MOBO: MSI Z97 Gaming 5 LGA 1150
CPU: Intel Celeron G1840 LGA 1150
RAM: 4GB (2600 MHz)
Windows 10

With -i 8
GPU's
1 x MSI AMD R9 390 8GB, 1081/1500 (speed with CM V12.1 = 380 H/s)
1 x Gigabyte AMD Gaming G1 R9 390 8GB, 1065/1500 (speed with CM V12.1 = 388 H/s)
2 x XFX AMD Rx 480 Rs 4GB, 1400/1720 (speed with CM V12.1 = 290 H/s)


All running very well