12.4, Win 10, driver 15.12

Sapphire R9 280 Dual X @ stock bios, 1100/1500, i:5, asm: 1 ~295H/s@ ~200W
Sapphire R9 290 reference @ 390 bios, 1100/1250, i:6, asm: 1 ~400H/s@ ~260W