I'm planning to buy a Gigabyte B450 DS3H motherboard for ryzen 5 2600. Do I have to "BIOS" update the motherboard to put a ryzen 5 2600? I just want to make sure.
Should be supported out of box, but check for mobo web site suppoerted cpu list to be sure if out of box bios is supported
No, B450 was designed for Ryzen 2nd Gen so you should be able to pop it into the socket and good to go.
B450 and X470 have Ryzen 2000 series support with all BIOS versions
A BIOS update is only needed for Ryzen 3000 series processors