When building a computer, many people overlook the importance of choosing a good power supply. Usually this is because it's not very exciting or doesn't provide obvious benefits to the finished product.
However, a good power supply does more than just provide electricity to your system. It can deliver clean and stable voltage to avoid system crashes. A power supply unit needs to provide enough juice for the computer to run. Choosing the right power supply for your computer can save you a lot of headaches in the future. Using the wrong power supply can not only shorten the lifespan of your components but can also damage them. Suppose a power supply can't handle the power load of all the components in your build. In that case, you may experience crashes, freezes, data loss, or component failure.
A high-quality power supply unit (PSU) is essential for creating a reliable computer that will last.
If you’re building a new PC or replacing an existing power supply and aren't sure how to pick a good power supply to match your needs, then this guide is for you.
Check out my Recommended PSUs below.
The main job of a power supply is to convert the alternating current (AC) from your wall outlet into the direct current (DC) needed by the components inside your computer.
PSUs with higher efficiency ratings use less energy and produce less heat, improving their reliability and reducing noise.
The 80 PLUS certification program for power supplies helps to promote energy efficiency by indicating its efficiency rating.
Higher-efficiency power supplies may have a higher upfront cost. However, they can also save you money on electricity in the long run. I've experienced firsthand that utilizing a PSU with a high 80 PLUS efficiency rating can significantly reduce energy usage, heat production, and power costs, depending on your usage patterns.
Lower wattage PSUs will be more power-efficient even when idle. For this reason, you may be able to save more on electricity by getting the correct wattage of PSU than by getting the one with the best 80 PLUS rating.
|Certification Level||10% Load||20% Load||50% Load||100% Load|
|80 Plus Bronze||82%||85%||82%|
|80 Plus Silver||85%||88%||85%|
|80 Plus Gold||87%||90%||87%|
|80 Plus Platinum||90%||92%||89%|
|80 Plus Titanium||90%||92%||94%||90%|
An important factor when buying a PSU is the supported wattage.
You can estimate your power needs by using the following chart.
|Component||Peak Power Usage|
|Top-Tier CPU (e.g. Intel's i9-13900K)||253 W|
|Mid-Tier CPU (e.g. Intel's i5-13600K)||181 W|
|Top-Tier Graphics Card (e.g., Nvidia RTX 4090)||450 W|
|Mid-Tier Graphics Card (e.g., Nvidia RTX 3060)||170 W|
|Optical Drive||30 W|
|3.5" Hard Drive||9 W|
|M.2 or 2.5" SSD||9 W|
|140 mm Case/CPU Fan||6 W|
|120 mm Case/CPU Fan||6 W|
|80 mm Case/CPU Fan||3 W|
By adding up these numbers, you can estimate peak power usage.
With four SSDs and three large case fans, a top-tier computer could see peak usage of 864 W.
It's generally a good idea to add a 100–150 W buffer to your expected usage. This buffer will give you some flexibility in case of miscalculations and will allow you to add more drives, fans, or add-in cards in the future.
In the above top-tier computer example, a 1000 W power supply would be a reasonable choice.
In most cases, buying a little more wattage than you need is a safer choice for ensuring system stability.
Don't forget to account for the additional power required for overclocking if you intend to overclock your CPU or GPU. Overclocking could require roughly an extra 50–100 W, depending on how much you overclock these devices.
Make sure your PSU has the correct connectors to support the hardware in your system. Cheaper PSUs may cut costs on connectors and cables by offering fewer options and shorter lengths.
Check with your motherboard and graphics card documentation to determine which connector types are needed. Buy a popular, recently-released PSU; it will likely have the necessary connectors for a new PC build. However, if you use old components or an old power supply, you may find some incompatibilities.
Here are some common connector types that power supplies support:
- 24-pin connector for the motherboard
- 4/8-pin connector for the CPU
- 6/8/16-pin connectors for graphics cards
- SATA Power connector for each SATA HDD or SDD storage device
The latest graphics cards and ATX 3.0 PSUs support a new 16-pin PCIe 5.0 connector that replaces multiple 8-pin connectors.
Typical power supplies come with various cables to connect your components. However, extra unused power cables can work against you by interrupting airflow.
In comparison, modular and semi-modular power supplies allow for attaching only the cables you need. As the name implies, semi-modular power supplies have some wires soldered on, while you can optionally connect others.
Most power supplies will have cables long enough to support mid-sized towers comfortably. If you have a full-size tower, you may want to check reviews and documentation to ensure that the cables are long enough to allow good cable management. In my experience building computers, I have discovered the inconvenience of power supplies with short cable lengths. Short power cables can pose a massive challenge when reaching the necessary components, making case layouts look cluttered and obstructing airflow.
Power Supply Form Factors
Various form factors are available for power supplies, but most PC gamers will want the standard ATX power supply.
Small form factor PSUs allow for usage in many computer case shapes, including mini-PCs.
Power Supply Features
Overvoltage protection and short circuit protection can save your components in the case of a surge or accident. I've experienced multi-component failures before and would prefer a PSU with these protective features to avoid buying a whole replacement system when the cause is preventable.
LED lighting is another feature you might consider, depending on the goals for your PC build.
You may live in a dorm or a family member's house and not pay electricity bills. Or you don't expect to use your computer daily for an extended period. In those cases, the lower upfront cost of a less efficient PSU may be the better choice. I once lived in a dorm without having to pay for electricity. With moderate computer usage, I decided to try a less efficient PSU to save on upfront costs. It helped me in that situation.
On the other hand, if you care more about your electric bill or the environment and plan to maintain higher CPU or GPU usage, a more efficient PSU may be better. As I became more conscious of my electric bill and environmental impact, I observed that my high CPU and GPU usage took a toll. So I researched and analyzed my options. Based on my findings, I invested in a more efficient PSU. It was a decision that paid off, as I saw a noticeable decrease in electricity costs over time.
Stay under 150 W above your expected power needs. Rightsizing your power supply will keep electricity costs to a minimum, as higher-wattage PSUs consume additional power, even when idle. I've experienced a situation where I chose a PSU that exceeded my power needs by a significant margin. Unfortunately, I learned the costly way that when my computer was idle, the high-wattage PSU consumed unnecessary additional power. This experience made me realize the importance of rightsizing my power supply to keep electricity costs to a minimum.
I've come to understand the significance of considering my specific circumstances and needs when choosing a PSU. Whether it's about saving costs or reducing my environmental footprint, making an informed decision is beneficial in the long run.
Recommended 750-1650 Watt ATX 3.0 PSU
Thermaltake Toughpower GF3 ATX 3.0
The Thermaltake Toughpower GF3 ATX 3.0 Power Supply on Amazon (affiliate link) is our recommended 750-1650 watt ATX 3.0 PSU.
We were impressed when we saw the efficiency rating of the Thermaltake Toughpower GF3 ATX 3.0. Its GOLD 80 PLUS efficiency rating ensures the power supply operates at peak efficiency, reducing energy waste and operating costs.
With support for the ATX 3.0 standard, the Toughpower GF3 is an excellent choice for anyone looking to upgrade to newer graphics cards, ensuring compatibility with the latest hardware releases.
The fully modular cabling on the Toughpower GF3 allows for easy customization and cable management, optimizing airflow and minimizing clutter in my build.
The ultra-quiet design of the Toughpower GF3 makes it an excellent choice for anyone looking for a power supply that won't add excess noise to their system, even under heavy workloads.
This series of power supplies comes in power outputs including 750, 850, 1000, 1200, 1350 and 1650 watts. Thermaltake Toughpower GF3 Series 80+ Gold Full Modular ATX 3.0 PCIe Gen 5 Power Supply Check Price on Amazon Amazon Affiliate Link
Recommended 650–1000 Watt PSU
Corsair SF Series PSU
The Corsair SF Series Power Supply on Amazon (affiliate link) is our recommended 650–1000 watt PSU.
The GOLD 80 PLUS efficiency rating of the Corsair SF Series PSUs impressed me when I saw it, as it ensures that the power supply operates at high efficiency and saves on energy costs.
With fully modular cabling, the Corsair SF Series PSU allows for easy customization and cable management, improving airflow and minimizing clutter in my build.
I appreciated the near-silent operation of the Corsair SF Series PSU during low usage, which provides a quiet and distraction-free computing experience.
This series of power supplies comes in power outputs including 650, 750, 850, and 1000 watts. EVGA SuperNOVA G5 Series Fully Modular Power Supply (220-G5-0650-X1) Check Price on Amazon Amazon Affiliate Link
Want to brush up on other new technologies to consider when building a computer? Check out these articles:
- The Best CPUs for Gaming
- Which Intel and AMD CPUs Support PCIe 5.0?
- Which Intel and AMD CPUs Support PCIe 4.0?
- LGA 1700 CPU List
- LGA 1200 CPU List
- Look up an Intel or AMD CPU on TechReviewer for related recommendations:
- CPU Coolers:
- Graphics Cards:
- Power Supplies:
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