The trend of increasing heat densities in data centers has held consistent with advances in computing technology for many years. As power density increased, it became evident that the degree of difficulty in cooling these higher power loads was also increasing. In recent years, traditional cooling system design has proven inadequate to remove concentrated heat loads (20 kW per rack and higher). This has driven an architectural shift in data center cooling. The advent of a newer cooling architecture designed for these higher densities has brought with it increased efficiencies for the data center. This article discusses the efficiency benefits of row-based cooling compared to two other common cooling architectures.