Choosing the Right Power Supply Unit (PSU)

By Samuel Wilson

In a computer build, people often times overlook the fact that a quality power supply unit (PSU) is needed to make the system run efficiently. All the components in a computer will need to draw a certain amount of power in order to function properly. An adequately rated power supply unit is needed to make this happen. A low wattage PSU might cause the computer not to start, or even restart while in use. In order to avoid all of this, a little bit of planning needs to take place in order to avoid major issues in the future.

The PSU that’s chosen to fuel the computer will need to be able to handle the power draw of all the devices attached to it. Various components such as higher end CPU’s and graphics cards will require additional power in order to operate. Other things, such as using several hard drives and/or expansion cards will play a role in how much power the computer will consume.

The first thing to consider, is how much power is actually needed. This will be measured and determined in watts. Due to the different needs of various build types, there isn’t a cookie cutter and exact template, for how much power every type of build needs. With that being said, here is some information to make things easier and to help ensure a PSU with the correct wattage and specifications is selected.

For a basic computer build without a graphics card, it’s possible to get away with a 400w power supply, but preferably a 430w-480w power supply would be best. Mid-range computer builds will generally do fine with a 500w-700w power supply. This should be enough to power all components in this type of build (CPU, Graphics Card(s), Drives, etc).

Now on to a High-End computer build, a 750w or greater power supply may be needed for this setup, especially if multiple GPU’s were selected. These High-End computers will be utilized for top of the line gaming, video/multimedia editing, and various demanding workloads. Higher wattage power supplies are necessary to fuel all the components (multiple GPU’s, high-end CPU’s, several hard drives, and expansion cards) all at once. A 1000w power supply may be needed if the system is going to be running multiple GPU’s that have higher power requirements such as the AMD R9 390X (

Look for power supplies that are properly rated and have an 80 Plus certification. These certifications have “different levels” that include: 80 Plus, 80 Plus Bronze, Silver, Gold, Platinum, and Titanium. They are ordered in level of efficiency, with Titanium being the highest and most expensive. Most users will be completely fine with an 80 Plus Bronze certified power supply. On the other hand, enthusiast and various high performance setups will benefit and/or require more-efficient power supplies.

When power supplies operate within their peak efficiency, they don’t draw as much power. When selecting the wattage and the 80 Plus certification for the PSU, be sure to check out the manufacturers’ product specifications prior to purchase.

It’s a good idea to try and make sure the computer operates within the peak efficiency of that particular power supply to ensure a great deal of power isn’t being wasted.

Regardless of the 80 Plus rating, the power supply still needs to provide sufficient power in watts to properly run the computer. When a computer doesn’t  operate within peak efficiency, the system will draw more power than is needed and will result in a higher electric bill.

Some terms to look for when selecting a power supply unit are continuous wattage and peak wattage. Continuous wattage essentially indicates the amount of power that can be delivered on a consistent basis. The power supply should list this figure and sometimes, it will list this information along with the peak wattage. These are good things to lookout for when researching power supplies.

Peak wattage essentially refers to the highest amount of power that can be delivered. There are several variables in determining this number and there really isn’t a definite standard. It’s not a good idea to make a decision solely based upon peak wattage. With that being said, stay away from power supplies that just list peak wattage.

The term modular, when referring to a PSU, generally means the peripheral power cables aren’t directly attached to the unit. You only attach the cables that are actually needed to power the devices in the build. This will help to aid in cable management and can cut down on clutter inside the computer case.

Please don’t use cheap power supplies from an unknown manufacturer, that is a recipe for disaster. Computer components can be damaged or a fire may break out as a result of using a cheap and/or unreliable power supply. To avoid problems and safely power a computer, make sure a PSU is selected from a known and credible manufacturer, such as Fractal Design (

Here are three PSU’s made by Fractal Design that will work great in different build types. Budget Build: Integra M 450W (80 Bronze), Mid-Range: Integra M 650W (80 Bronze), and High-End: Edison M 750W (80 Bronze Gold). Fractal Design also produces quality affordable computer cases that look great, along with case fans, water cooling systems, and various computer accessories.

To help achieve the best results from a computer build, the right PSU needs to be selected. Do a little bit of homework and check the power requirements of the PC components and it should be smooth sailing when it comes time to purchase a PSU. Stay tuned, as I discuss what else is needed (peripherals, accessories, hardware, etc.) to make this computer build a success. For more information visit

Print Friendly, PDF & Email