My results:
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Windows 10 Pro 1709
Drivers Adrenalin 18.6.1
SRBMiner V1.6.5
Custom memory timings
Overclock 1260/2100 900-910mV
Cryptonight V7
intensity/worksize/threads: 57/8/2
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RX570 4GB Hynix        992 H/s
RX570 4GB Samsung  1020 H/s