How to Calculate PC Power Supply Sizes

The power supply of a computer is the device which translates the current from the outlet into a form which is usable by your PC's hardware. When calculating the power supply size, it is always better to overestimate rather than underestimate, as there is no penalty for guessing high. Therefore, the best place to begin calculating the power supply requirements of your computer is by looking to the "hungriest" component---the graphics card.

Instructions

1. Consult your graphics card operating manual and look under the "System Requirements" section.

2. Locate the entry which reads "Recommended Power Supply"---this will provide you with a baseline number for your calculations.

3. Add 50 to 100 watts to that number to provide yourself with a margin of overhead.

4. Add another 50 to 100 watts if you are running a "non-standard" system. For example, if your system contains more than one hard drive, more than two optical drives, more than one graphics card, or any other additional component that would increase your power needs above and beyond that of a "regular" computer.

References

• Cheap Computer Guide: Power Supply Requirements