im about to transition to an amd rx 580 , what are some of the things i should do/change before actually swapping the cards?

im running atm a nvidia GPU with web drivers on the latest high sierra and this is my hardware
CPU: I5 3470

Motherboard: dq77mk

and im running on iMac13,2;

my assumptions are that i should uninstall the driver and remove the flags about nvidia? Do i have to change the smbios too? Am i missing something else?

thanks!