The PSU (power supply unit) supplies electrical power to your PC and its components, including the motherboard, hard drive, and graphics card.
Installing a PSU isn’t difficult, but it’s important to ensure that you connect all the components correctly. Choosing the correct PSU for your gaming PC is also critical, as a low-end power supply unit might not provide enough power for robust gaming rigs.
Choosing A PSU For Your Gaming PC
There are four things to consider when buying a PSU:
- Form factor
The most significant factor when buying a power supply unit is its wattage. 500W of output is the bare minimum, but if you have high-end PC components, such as an Intel i9 processor or multiple graphics cards, consider buying a PSU unit with at least 750 watts and possibly more – up to 1200W or even 1300W.
It’s better to err on the side of caution, as having a more powerful PSU doesn’t come with many drawbacks other than the additional cost. It also gives you more flexibility, allowing you to install more powerful components later.
Newegg has a helpful calculator for determining your required wattage based on your CPU, GPU, and other components.
Always buy a PSU with at least 100-200 extra watts to account for spikes in power usage.
If your PSU isn’t powerful enough, your system may experience lags, crashes, or random shutdowns.
For most gaming rigs, you’ll be buying an ATX (Advanced Technology Extended) form factor PSU, which fits in computer cases that support ATX and micro-ATX motherboards. SFX (small form factor) PSUs exist as well, but they are much smaller and tend to be less powerful than ATX PSUs. They are only recommended if you have a mini-ITX or a smaller motherboard.
Another factor to consider is whether the PSU is modular or non-modular. Most PSUs are non-modular; they come with multiple cables permanently attached.
Meanwhile, modular PSUs have empty sockets that allow you to pick and choose which cables to plug into the unit. The benefit of a modular PSU is that you can save space in your computer case by removing cables you aren’t using. It also gives you more flexibility over which cables you insert, depending on the PC components you install now or down the line.
Most modular PSUs come with a variety of cables in the package, but they tend to be more expensive than non-modular units.
Semi-modular PSUs come with the basic cables, such as CPU and motherboard cables, permanently attached, but give you flexibility over the others. The price point tends to be between non-modular and fully modular PSUs, making it an excellent choice for those on a mid-range budget.
Finally, it’s important to buy a PSU with voltage appropriate for your region. In North America, appliances use 110V, while in Europe, they use 220-230V.
If you connect a 110V PSU to a 220V outlet, it may cause an electrical current surge that can fry or blow out your computer components. If you connect a 220V PSU to a 110V outlet, it may not turn on at all.
Some PSUs come with a voltage switch or button that allows you to set the voltage depending on your region and socket. Make sure the voltage switch is set correctly before powering on your PC. If you travel with your PSU to another region, change it accordingly.
Installing the PSU In Your Computer Case
In some PC cases, the PSU goes in the top, while in others, it goes on the bottom. Look for a rectangular or square area with a removable cover on the case to see where your PSU goes.
Remove any screws holding the cover in place. Next, insert your PSU into the case and into the slot (you might have to open up the side or bottom of your case to get it in), aligning the four mounting holes on the PSU with the four holes on the case.
Never insert any object inside the vents of the PSU, and make sure your computer is disconnected from the power supply before working on any components.
PSUs typically have an intake fan and an exhaust fan. The exhaust fan should face outward – together with the connector that connects the unit to your wall socket. This is likely also where the power switch on the PSU will be located.
Meanwhile, the intake fan should ideally face the outside of the case. That allows it to draw cool air from outside the case into it, cooling down your PC components.
However, if there is a metal case wall blocking the intake fan, with no ventilation areas (as is common with older cases), or if you have a carpet blocking airflow, install the intake fan facing inward, into the rest of the PC. That way, it will draw hot air from inside the case and expel it outside the case.
If you have a non-modular PSU, fitting the unit inside the case may be a bit tricky, as the cables can get in the way. It might help to connect the cables to the components first and then insert the PSU into the case.
Once the PSU is in its slot, use a screwdriver to screw in the four screws and secure the PSU in its place. Avoid using a drill when working with PCs, as they can easily cause irreparable damage.
Connecting The PSU Cables To Your Internal Components
After installing the PSU, your job is not done yet. You need to connect the cables from the PSU to the relevant components, so they can draw power from the unit. This is the fiddliest and most difficult part of the process, but it is still as simple as finding the right places to plug in cables in your PC.
There are a few types of connectors you will see coming out of your PSU.
The first is the ATX connector, which supplies power to your motherboard. They come with 20 or 24 pins.
The 20-pin version is the older standard, but most modern motherboards require a 24-pin cable. Some ATX connectors come in a 20+4 style. These are two separate connectors, one with 20 pins and one with four, that you can connect to make a 24-pin connector.
Meanwhile, ATX12V connectors, which have four, six, or eight pins, provide power to your CPU. Most modern CPUs require an eight-pin connector, but some ATX12V cables come with a 4+4 connector, similar to the 20+4 ATX connector.
SATA connectors are used to connect to SSDs, hard drives, and optical drives, while PCIe (PCI Express) cables will connect to your PCIe graphics cards.
While PCIe graphics cards get some power from the PCIe slots they are installed in, high-end graphics cards may require additional power. PCIe connectors come with six pins, eight pins, or 6+2 pins.
Molex connectors, also called standard connectors, are less common nowadays and have been slowly falling out of use, but they may still be required to power your fans. In the past, they were used to power optical drives, IDE drives, and other components.
Most power supply units will come with a Molex connector or two, even though they are considered legacy connectors.
If you don’t have enough cables to power all your units, buy a Y splitter, which is a small cable that connects to a cable and splits it into two. A Y Molex or SATA connector, for example, can turn one Molex or SATA connector into two separate ones.
There are also adapters that turn one type of connector into another, such as a Molex connector to a PCIe connector.
When using Y splitters or adapters, make sure the components don’t draw more current than what the original cable would have been able to provide.
If there are excess cables in your PC case after installation, use a zip tie or cable tie to tie the extra cables together, so they are organized and don’t block airflow.
Once you’ve connected all the cables, you can close your PC case, plug your PSU into the wall socket, and power on your PC.
NEXT: A Beginner’s Guide To Installing A CPU For Your Gaming PC