Now using Claymore 11.3 mining Monero with -pow7 1 and it works wonderfully.
All my RX 570s hashing at 850-855H/s

Claymore, you are the champ!
Can you give me the detail of config, thanks ?
Sure,
this is my command line
NsGpuCNMiner.exe -pow7 1 -h 928 -dmem 1 -xpool stratum+ssl://europe.cryptonight-hub.miningpoolhub.com:20580 -xwal bobben.%computername% -xpsw %computername%
The above -h value is for 4 gig cards. If you hasve 8 gig cards, then you can set that value higher.
I use OverdriveNTool to set gpu core clock (P7) to 1150 and mem (P2) to 2000.