I tried to increase GPU voltage, it's helps on neoscrypt for sometime. Thread hangs not so quick, but on cryptonight it didn't helps at all. I use lowered clocks for my 580 cards. I use 1245MHz GPU clock. Lowering it decreases speed - and this is not good for me.
Increasing the voltage works well but it's not so good assuming ^2 power usage, so at home I can only lower MHz at GPU and mem. Ye, decreasing speed this way.
On cryptonight increasing voltage didn't work. I tried up to 1000mV with the same 1245Mhz vcore. On 17.11.4 card stable works with 1245MHz and 950mV. I stop it, becase I don't want to lose speed or inrease power consumption and temp.
I'll wait while zawawa take full control on 17.12.x drivers, or AMD release new version. If it didn't helps in future, I'll return to 17.11.4 driver.