PSA: PSU Power/Cable Requirements and High-End Graphics Cards

PowerSpec_MichaelB · March 2022

Introduction:

For quite some time now, PSU requirements have evolved to match the ever-growing hardware performance of our systems. Not too long ago, you could get a 600W PSU and a high-end GPU/CPU combo and be fine. Those days seem to be behind us with the latest iteration of high-end gaming hardware. With GPU's in particular, we've seen power consumption increase tremendously and standards evolve to match those changes. The RTX 3090 for example, can consume upwards of 350W at stock boost settings, and exceed over 420-450W with simple power limit adjustments during overclocking.

What does this mean for PSU's and their cable requirements? That's a great question.

Power Requirements:

When we think of PSU compatibility with our components, the first thing that comes to mind is capacity. How much capacity do we need for our components and whether we have enough cables on our PSU to connect all of our hardware. To answer these questions, we can make use of PSU calculators which factor in our configured system hardware to give an estimate based on typical loads for that specific system configuration. Still, it's always better to have more and not need it than to need it and not have enough. Speaking of PSU calculators, our Custom PC Builder Tool happens to have an integrated wattage calculator for those of you that need help planning around your hardware configuration: https://www.microcenter.com/site/content/custom-pc-builder.aspx

Power Supply Cables:

As mentioned previously, ensuring you have enough cables for your component configuration is just as important as ensuring you have the capacity to deliver power to your hardware. After all, what good is a 1200W PSU if you don't have enough cables to connect all of your hardware? Check product specification pages on your PSU to determine the cable configuration and ensure you have sufficient power connectors.

Another important caveat of PSU cables involves high-power GPU's. You may encounter cables with multiple power connectors attached to them, such as PCIe power cables. These are commonly referred to in the industry as "pigtails" and worked really well when hardware power requirements were not as demanding as they are now. For high end cards such as the RTX 3000 series and AMD 6000 series, it's ill-advised to use these connectors. Instead, we recommend running a single cable per 8-pin connector as it can prevent damage to both your PSU and connected components.

Connecting PSU Cables to a high-end GPU:

So how exactly should one connect their PSU cables to their high-end GPU? Here is how we would do it:

In our example above, you can see the RTX 3070 Ti on our test bench has two separate cables leading to the 8-pin ports on the card despite having multiple 8-pin connectors on each cable. This ensures we are distributing the current across multiple sets of cables and will prevent us from potentially damaging cables or components in the event of excess power draw. If your card requires 3 8-pin connectors, it would be best to use 3 separate cables. This is why we always recommend investing in a high-quality power supply to complement your high-end system components.

Conclusion:

When it comes to our high-end components, it's always safe to err on the side of caution in order to improve longevity and ensure reliability. If you have questions about your PSU/component configuration, feel free to post your component list in the comments and we will help you decide how best to connect your hardware. If you are interested in building a new system but are hesitant to perform the assembly, you can always visit our Micro Center stores and take advantage of our many build services: https://www.microcenter.com/site/service/instore-custom-pc-build-services.aspx.