Tryid it on 280x
Got 12-13mh per one(8.1x64, cm9.
...nothing change from 15.12 driver. Stupid amd didn't applied their fix to truly good cards 
Got 12-13mh per one(8.1x64, cm9.
...nothing change from 15.12 driver. Stupid amd didn't applied their fix to truly good cards It didn't change because the R9 280x didn't suffer from the issue that the driver was intended to fix.
The 280x was never a "truely good" ETH card in the first place - that was the 290 and to a lesser degree the 290x.
Tahiti is arguably the best performance/price ratio for FP64 anyone ever released, but ETH doesn't use floating point....