Lermite kindly provided optimal config for RX570, it may be good on RX580 too.
Using 100% memory is good for CN-Heavy but not always for CN-v8
RX570 4G
"gpu_threads_conf":
[
{ "mode": "GPU", "worksize": 8, "alpha": 64, "beta": 8, "index": 0, "multi_hash": 976 },
{ "mode": "GPU", "worksize": 8, "alpha": 64, "beta": 8, "index": 0, "multi_hash": 976 },
]
RX570 8G
"gpu_threads_conf":
[
{ "mode": "GPU", "worksize": 8, "alpha": 64, "beta": 8, "index": 1, "multi_hash": 1008 },
{ "mode": "GPU", "worksize": 8, "alpha": 64, "beta": 8, "index": 1, "multi_hash": 1008 },
]
For my 2 RX 580 8G cards best multi_hash parameters for v8 are multiples of 96. Such as 1104, 1200 etc. Higher - speeder. Best is 1680, 1776 and 1872.