after 10 days tweaking i find this option 
thank you for great information!
I've done to follow instruction but somehow when I disable/enable Vega56 on device manager 1 of 2 got exclamation mark when it's enabled and isn't detected when mining.
I clean installed Win10 64, AMD Blockchain driver "Only" is installed manually, Set "0" to both EnableElps, EnableCrossFireAutoLink. and followed rest of instruction...
a restart fixes it. this happens before the disable/enable, the card just has not loaded the driver properly at startup, thats the problem.
I've restarted over 10 times but nothing has changed.If it could solve just restart I wouldn't ask to bother this thread.
In case I reinstall Win10 again since my previous post and followed instruction as 2nd time but same...
It wasn't effective for my case...