@epicfailman
which driver/miner use you?
I use sgminer-nist5mod v4.1 with 14,43 mh per card, but it's very old... gatelessgate is very stable but max hasrate is 14,07 mh and it have few information... sgminer-gm crash about 2-3 hours.... I have driver 16.11.5 foe window 10
Now sgminer 5.6.0. RX480+RX460. 23MH+10MH
tomorrow will change RX460 for 470.
Also i have 7990HD, 58MH, but now it working on main farm (ZCL). For Equihash algo it is best of the best. 600 H/s
UPD
OS - Windows 7 x64
Driver - Last 17.3.2