The power supply is the most vital component inside your desktop PC. This single part takes alternating current (AC) from your power outlet and converts it to a more reliable direct current (DC) that all PC components can use. The PSU also has numerous safety measures available to protect the PC from power surges, drops, or other changes in delivery. When looking to build a gaming PC, you must choose the right PSU for the job, especially when considering more powerful graphics cards. Here’s everything you need to know.
Don’t save too much money on a PSU
Spending too little could have disastrous consequences
You can buy a terrible power supply, even from a reputable brand. This is why it’s important to consider the specifications of a power supply, the components used to make the product and the price. Spending too little on a power supply is a bad idea that could have disastrous consequences. It’s powering everything inside your PC, including that expensive graphics card.
There are many brands out there with power supplies available for desktop PCs. These include Asus, be quiet!, Cooler Master, Corsair, DeepCool, EVGA, MSI, NZXT, Seasonic, and Thermaltake. Picking a PSU can prove challenging if you’re unsure what to look for. Picking the best PSU for gaming can be as simple as factoring in wattage requirements and other desired specifications.
I would recommend consulting the excellent Cultists PSU Tier List. Just because a reputable brand makes a PSU, doesn’t mean it will work flawlessly — Gamers Nexus found this out with Gigabyte’s GP-P750GM. Using the linked guide and one of our recommendations, you can be sure you’ll buy a reliable PSU that won’t cause trouble. I would recommend spending at least $100 on a power supply.
Choose the right PSU capacity
You can choose too little or too much
A power supply can only provide so much direct current to the PC. This is displayed on the side of the unit and in marketing on product pages. Power supply products from various brands can also come in different capacities, like a hard drive or SSD. The higher the capacity of the PSU, the more power it will be able to output to connected hardware, but it will also cost you considerably more.
AMD, Intel, and Nvidia all display the power draw of their graphics cards on each product page. This value can then be added to the power draw of the CPU, motherboard, and other parts of the PC. A good rule of thumb is to provide an additional 100W on top of the combined GPU and CPU power requirements to factor the entire PC in.
Related
How do I select the right PSU for my PC?
Choosing the right PSU for your PC will save you a lot of wasted time and money
Efficiency should be considered when choosing a power supply for your PC. Power supplies have what’s known as an 80 Plus rating for efficiency. The higher this rating, the more efficient the power supply. Ratings start at Bronze and top out at Titanium. Here’s a quick look at all the different efficiency ratings and what they mean for power delivery at various loads.
|
Rating |
10% |
20% |
50% |
100% |
|---|---|---|---|---|
|
80 Plus |
— |
80% |
80% |
80% |
|
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% |
Let’s look at an example with an Intel Core i5-14600K processor and Nvidia GeForce RTX 4080 graphics card. The CPU can draw up to 181W of power. The RTX 4080 has a maximum draw of 320W. This is a combined total of 501W. Factor in my 100W buffer for the motherboard and all other parts connected to the PSU, we have a total of 601W. Nvidia recommends 750W for the RTX 4080 so this is about right.
With a 750W PSU, our system will run at approximately 80% load on the unit when the CPU and GPU pull their maximum power. A PSU runs at its best (and most efficient) at around 50% load, as illustrated in our 80 Plus table of efficiency scores. A PSU running at 80% (or even 90%) is not an issue but it will mean the PC as a whole will be sucking more electricity from your outlet due to waste through AC to DC conversion.
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How to match your CPU and GPU
A badly matched CPU and GPU can severely affect your PC’s performance, which needs to be avoided at all costs.
Check the PSU has the right ports
Standard PCIe vs. PCIe 5.0 12VHPWR
A power supply will be rendered useless if it’s unable to connect to your graphics card. Depending on which GPU you buy, it will use a 6-pin PCIe, 8-pin PCIe, or a 16-pin 12VHPWR PCIe 5.0 connection. A power supply built to the ATX 3.0 standard will support all three connections and will be able to handle any GPU on the market.
Older PSUs or new ones built to the older ATX standards will only work with 6-pin or 8-pin PCIe cables. This isn’t a major concern as only select Nvidia GeForce RTX 4090 and Nvidia GeForce RTX 4080 GPUs use the 12VHPWR PCIe 5.0 cable. It’s something to consider, so make sure your PSU is equipped with the right ports if using the best GPUs.
What happens if you choose the wrong PSU?
If your PSU does not have enough capacity to handle the hardware connected to it, the unit will shut the PC down. Modern power supplies have many safety guards implemented and the PSU will trigger one of them should the load placed upon it surpass its designed limit. At this point, you will need to buy a new, more powerful power supply.