I did all steps posted by @Vann still unusable Windows. I changed partition type from mbr to gtp reinstalled os 10 uefi with 1 rx580 in slot. turned off secure boot & csm. DDU in safe mode then installed adrenalin driver with all 12 gpu inserted. its almost impossible to use windows. i have to wait like 10 minutes to login windows. mouse is lagging. After waiting like half hour to get in, claymore error "miner didnt start for 5 minutes, restarting...". I also tried smos which is great but i dont want to use ethernet cable so i need windows.
Any suggestion ? Could it be motherboard ? Asus optimisation software shows 12 available gpu, everything is ok with raisers, except that windows is lagging.