In the Data Center industry, higher density server racks are becoming increasingly more common due to more powerful chips. About 15 years ago, a typical data center would be built to support 4-5 kW per rack. Data centers built about 10 years ago were built for densities between 8-10kW.
Today the majority of Data Centers still report server densities below 10kW, although some newer data centers are able to handle as much as 20 to 25 kW per rack.
Higher densities normally mean higher efficiencies as less space and equipment are necessary to perform the same job. However, the biggest challenge facing higher densities are cooling.