Modular power supplies have becoming a new standard in gaming PC's. Many people recognize the ability to have the bare minimum of PCIE, Molex, or Sata cables as their PC's require. With the rise of power hungry graphics cards, watercooling pumps, fans, and all the extra's we need our PSU's to run it can become important to distribute the load across evenly across the rails. Now if you have a single rail power supply then no need continuing, your golden; but not all PSU's are single rail setups. Multi-rail PSU's are common and accepted, even with modular supplies. One popular example is the Corsair HX 1000W power supply. A strong supply that can handle most everything. If you may be concerned with overloading the main CPU rail by connecting two 8 pin PCIE connectors, feel free to utilize the rail not dedicated to the CPU. The diagram below is straight from Corsair's forum: Please feel free to provide details on other popular modular power supplies or general comments on the subject.