If you go to this psu calculator and enter all your details of what you intend using, it will tell you the requirement. I've seen it recommended to raise what is suggested by about 3O%, which sounds like a good idea to me.
They are usually pretty straightforward to replace....take out the old and stick in the new in its place...wires and screws etc.
They are usually pretty straightforward to replace....take out the old and stick in the new in its place...wires and screws etc.