The energy source in which powers the computer is the PSU or Power Supply Unit. The PSU needs to be large enough to support your: Motherboard, RAM, Video card, CPU, other expansion slots, Hard drives and whatever additional features the case offers such as lights and display screens. Power supplies also come in “80 plus certified” which is very high energy efficient while still giving off the same wattage.
In order to choose the power supply right for the current setup the watts needed for all components should be taken into careful consideration. Having too little power going to the computer will cause some of the hardware to not function correctly or function at all. The power supply will come with the wires attached for connecting all components including motherboard and video card.