Oscar_11 :
an update on all this : my case is 16 inches wide
and a lot large
Exactly what case do you have?
A case that is 16" wide(ancho) sounds to me like a horizontal HTPC case which might have space issues with some graphics cards.
Is there a reason for specifying a AMD gpu as opposed to a NVIDIA gpu?
IN general, current AMD graphics cards are less power efficient and generate more heat.
That requires larger and stronger coolers that might be an issue in a small case.