Can PSU Bottleneck GPU? (5 Things You Need To Know)

GPU bottleneck has become one of the most common issues in recent times among gamers. Many users face the GPU bottlenecking issue and suspect their Power Supply is causing it.

In this article, we will walk through a detailed explanation of whether your Power supply is causing the bottlenecking issue or it is something else.

GPU bottlenecking means your GPU is unable to work at its fullest potential due to some other low-end components inside the PC. It is really difficult to avoid bottlenecking completely, but there are ways in which we can reduce GPU bottlenecking by picking the appropriate components.

An insufficient or faulty Power Supply can affect the GPU’s performance and reduce the framerates, but it cannot be termed a GPU bottleneck. 

The CPU is mainly responsible for GPU bottlenecking. Your GPU can only render the game’s frames if your CPU can process the information fast enough.

So, it’s always recommended by expert PC builders to pick the perfect CPU & GPU combo to avoid the bottleneck as much as it is possible.

A Power Supply Can Limit GPU Performance: Here’s How?

As mentioned, a Power supply can limit or affect the GPU performance, which mostly seems like GPU bottlenecking. Here, we will look at how a Power Supply can limit that and what we should do to avoid these performance issues-

Enough Wattage

Picking the correct wattage Power Supply is important because it will impact your system’s performance. Unfortunately, many beginners buy a Power supply with low wattage, so their system suffers a lot.

The GPU is the most power-hungry component inside our system, and if we use any low-wattage power supply with a high-end graphics card, the system will definitely suffer.

Suppose our overall system requires 500 watts of power at a high load & we are only using a 500 Watts Power supply; in this scenario, our components will work, but the GPU will not work at full potential.

That’s why picking a PSU with a littlebit higher wattage is really important.

If you are still determining how much wattage your entire components will consume, then you can use the websites like, and by choosing all your components, you can check your estimated power consumption.

Don’t Use Adapters like Molex To PCIe

The low-end graphics cards consume the power directly from the motherboard’s PCIe slots. But the mid-range & high-end GPUs need to be powered separately.

A graphics card must be powered separately when it consumes more than 75W power. Modern Power Supplies come with all the PCIe cables, such as 6-pin cable (75W), 8 Pin Cable (150W), and 12-pin cable (600W).

But, the problem appears when you have a high-end graphics card and an old Power supply that doesn’t have the required 6-pin or 8-pin PCIe cables.

In this kind of scenario, users try to use some adapter like Molex to PCIe, but using this adapter can limit your GPU’s overall performance.

Let’s understand this in-depth-

According to the evga the ATX standard for SATA or Molex connection is rated for 54 watts. Let’s suppose you are using a GPU that consumes 130 watts of power, and you don’t have sufficient PCIe cables in your Power Supply.

In this kind of scenario, if you use a dual Molex to SATA adapter, it would only be able to supply 54+54= 108 watts, while your GPU needs 130 watts.

Your graphics card can still work, but you will notice performance drops, and in worst-case scenarios, your graphics card can stop working.

That’s why the experts recommend never using any PCIe adapters with high-end or mid-end graphics cards.

Non-branded PSUs

Some Power Supply brands use cheap integral components (capacitors, transistors) inside; therefore, these PSUs fail to perform according to expectations.

Moreover, these non-branded PSUs don’t have voltage stability, and if you use these PSUs, then your PC will face system instability issues which will definitely affect the GPU’s performance.

That’s why using a branded power supply is highly recommended to get the maximum performance from your GPU. Some of the renowned PSU brands are-

  • EVGA
  •  Cooler Master
  •  Corsair
  •  Seasonic
  •  MSI
  •  Thermaltake
  •  Enermax

Not Using 80+ Certification PSU

It is always recommended to use an 80+ certification power supply because this certification indicates the actual efficiency of the Power Supply.

If you don’t buy an 80+ certification PSU, then your graphics card won’t be able to work to its full potential under heavy load.

So, if you are going to run AAA title games & if you have enough money, then go for the “80+ gold” or above because these PSUs are 90% efficient.


Overclocking increases overall PC performance, but at the same time while overclocking your PC components consumes more power than usual. So, if you are going overclock without extra PSU wattage, your PC components, including the GPU, will suffer.

Do not overclock your CPU or GPU when you don’t have a potent Power Supply.

PSU Affecting The GPU Performance: Here’s What To Do?

If your graphics card is not performing according to your expectations, you have to check whether your CPU is bottlenecking. If the CPU is not bottlenecking, then check the Power Supply.

If your Power Supply is affecting your graphics card performance, then upgrading the Power Supply is the only option to increase the GPU performance.

Check all the parameters like- wattage, brand, proper cables, and 80+ certification, and buy a new power supply. You can also take the help of the website to select the appropriate power supply for your system.

Wrapping Up

A Power Supply does not bottleneck your graphics card, but using an insufficient PSU, a non-branded PSU, or PCIe adapters can affect the GPU performance.

So, check all your system components to notice which one is restricting your GPU from performing well, and then upgrade the component.


What is Bottlenecking In PC

Photo of author
Hi, I'm Pallab Mitra, the founder of this blog. I'm a computer enthusiast, and I'll be sharing my knowledge and expertise about PCs on this blog. Read More- About Me