The document discusses an experiment that measured the energy efficiency of different server operating systems. Quantitative data was collected on the watts consumed and threads run by servers using Ubuntu, Windows Server 2008 Core, and Windows Server 2008 with a graphical user interface (GUI). The findings showed the GUI version of Windows Server 2008 consumed 1.43 more watts on average than the hardware baseline, while the Core version only increased usage by 0.15 watts. Having a GUI required processing and rendering graphics, resulting in over 100 additional threads and approximately 1 more watt of power compared to non-GUI systems. Removing unnecessary components like graphics cards from servers could significantly reduce overall energy usage in data centers.