Here is some Tech info comparing radiators.
"Dual row radiators and heater cores have a greater heat rejection capability than single row, but to utilize the higher capability stronger fans must be used to overcome the airflow resistance. Stronger fans make more noise and it was found that with an upper limit of 34 db(A) there is no way to achieve higher performance using a dual row core similar to those tested. Some may ask: What is a radiator’s ‘rating’? The answer is ‘it depends’. Specifically any ‘rating’ will, indeed must, define the flow rates on both the air and liquid sides and the temperature difference between the two sides. All of the thermal resistance and dissipation graphs above describe the ‘ratings’ of these radiators, but the air side flow rate is not known, only the air source (the fan) is held constant. Putting a more, or less, powerful fan on the radiator would necessitate new curves to define its ‘rating. There is no single value that describes a radiator’s ‘rating’ without also stating the flow and temperature conditions."