Extra Large Capacity Dryers
Generally have the same size heaters and gas burners blowers etc as the regular capacity dryers.
The largest models are only 15 to 25% larger, the purpose of the larger drum is to allow larger loads and more room for clothing to fluff up and reduce wrinkles, but they are not generally faster, electric dryers are limited in the US to about 5,600 watts by convention.
In any case the largest dryers are never slower drying the same load.
John L.