How Big Should My Computer Power Supply Be?

Strong power supplies are one way to keep up with your future computer needs.

Smaller Power Supplies Cost Less

Power supplies are one of the biggest ways that computer manufacturers cut costs, both on the quality of the power supply (how long it will last) and on how much its peak output will be. While there is a common misconception that a smaller power supply will be more environmentally friendly, that is false -- the wattage of a power supply is the peak output it can put out; the actual energy used will depend on how you use the computer. Low-end computer systems can come with 250-watt power supplies.

Modern Hardware Takes More Power

Power supplies have gotten larger in terms of their outputs over the years, because several components on the computer systems take more power to use. The big culprits are faster spinning hard drives and high end video cards, though CPUs are also a big contributor. Plus, any USB devices that power off the motherboard will also ramp up the power draw as well. Most "production" desktops come with 500-watt to 650-watt power supplies. Larger 850-watt and 1,000-watt (one kilowatt) power supplies for desktops aren't unheard of.

Bottom Line

If you don't do anything that needs high end performance on a computer, a 350- to 500-watt power supply will probably suffice. If you're doing video editing or high end computer gaming, you'll want at least a 650-watt power supply. If you intend to keep the computer for a long stretch of time, a larger power supply gives you more options to expand the system down the road.

References

• Efficient Power Supplies: How To Buy An Efficient Power Supply