With the seamless advancements in modern electronics and shrinking thermal real estate, a number of candidate thermal technologies have been developed. As system designers evaluate these methods, they require unambiguous comparisons in order to properly assess the positives and negatives of advanced solutions. The most commonly used metrics, particularly thermal resistance, are limited in their applicability, especially because they account for only for single factors like the temperature of the heated device. To improve these comparisons, a new volumetric enhancement factor, EFv , is proposed, which can be justified based on lumped capacitance arguments. When coupled with the thermodynamic coefficient of performance, EFv allows a simple comparison that relates thermal performance, system input needs, and system size simultaneously. Using these metrics, several advanced technologies are compared, demonstrating that liquid cooling using microchannels can be in excess of 1000 times more effective than air cooling methods.