Effects of server/rack locations and server loading configurations on the thermal performance of data center racks' array are experimentally investigated using a scaled physical model simulating real data. Front and rear rack temperatures profiles, server temperatures, and performance indices supply/return heat index (SHI/RHI) are used to evaluate the thermal management of the racks' array. The results showed that (i) servers located in high level rack cabinet have the worst thermal performance, (ii) middle racks of the rack row showed optimum thermal performance and energy efficiency, and (iii) locating the servers of high power densities in the middle of the racks row improves the thermal performance and energy efficiency of the racks array.