The majority of the servers that TechMikeNY sells are dual power supply unit servers, or, in other words, come with two power supplies. For the budget conscious, we do provide some configurations with one power supply and the option to add a second power supply. What is the advantage of having a redundant power supply? Simple: if one of the dual PSUs for a server should fail, the other unit will take over since both units are capable of handling the full wattage needed to run the server. For example, if your server pulls 500W total and there are two 750W power supplies installed, if one PSU fails, the other 750W power supply will provide enough power to keep the server running. Additionally, for servers in large data centers, each PSU can be put on a separate circuit – so should one circuit fail, the redundant PSU on the second circuit will take up the full load.