Hi, you're post make no sense.
You were saying that you were buying the 580 but the 480 is better?
It must be the other way around.
The 480 run really hot unless you buy a non-reference product, consumes a lot of power and is an older generation. So RMA might give you a weaker 5xx card.
It is also loud unless you use non-reference products.Also has DirectX11
The 580 run about 75 degrees(not sure) is a new generation, DirectX11, +15% percent performance over 580. Run cooler and quieter but consumes a lot of power.