Hi, "y" key at the initialization process of what?
For Claymore 14.7:
-y enables Compute Mode and disables CrossFire for AMD cards. "-y 1" works as pressing "y" key when miner starts. This option works in Windows only.
If you are running older version before "y option" implemented , you can change it manually one by one in "Radeon Settings" or use "amd-compute-mode-switcher-script" available somewhere on the internet.
Just use newest Claymore

thanks, will try with the latest Claymore, with the W10 1903 build update, my couple of RX480-580 switched to non compute mode and the Radeon settings doesn't opened anymore (it just appears in tasks but the window doesn't open)... I need to sort that out (I tried briefly to re-install the AMD driver, but then only one card was there in graphic cards instead of 2, reverted to latest restore point)