The rapid digitization of global activities is driving an ever-increasing demand for high-performance data servers in next-generation data centers, a trend that shows no signs of slowing down. The primary issue associated with the processing unit is the tremendous energy density released during data processing. It leads to localised heating, with high temperatures exceeding the safe working limits of many electronic devices. An extensive literature review shows the state of the art of existing server cooling technology with associated limitations. The problem identified is associated with the submerged cooling of a high-performance server. The present work is designing a 40-kW submerged liquid-cooled tank comprising 50 servers of 800 watts each. A numerical investigation has been performed on a single server to predict the system’s thermal performance. The commercial software Ansys Fluent has been used. The initial part of the work includes a theoretical analysis that determines the size of coolant pumps, chillers, storage tank size, server arrangement, and selection of coolant. A deeper theoretical study was also conducted to assess the maximum CPU temperature and the effect of the TDP of the CPU on its maximum temperature. The remaining part of the work is dedicated to the numerical investigation, which includes the thermal investigation of the existing server as a heat-generating body, the effect of the TDP variation of two CPUs from 85 to 500W, and the effect of the thermo-physical properties of four standard coolants: air, water, mineral oil, and EC-100. The outcome of the investigation reveals many interesting facts that were not understood earlier from a thermal management point of view. The result of the investigation is going to help the designers design and develop an efficient liquid-cooled submerged data centre.