Mine myriad-groestl coins at 1.5x speed with this standard sgminer binary kernel, compatible with the 290, 290x and 295x2 AMD cards.
Speed: 63 Mh/s on r9 290x @1100/150.
Reported working on AMD 390 as well (it's a modified Hawaii card in the end...) with a max speed of 60 Mh/s. Remember to put your memory clock as low as possible and use worksize 128.
Don't confuse this algo with pure groestl of Groestlcoin and Diamond. This is myriad groestl for myriad, digibyte, verge, etc.
0.2BTC =~ $206.19