GPU Power Connectors Explained

An often overlooked area when building a PC tends to be power consumption. A top of the line graphics card can significantly overbear the PSU, and that is something gamers do not want. So, to better understand how to power your GPU, we have prepared this resource for you.

Some low-end and some lower-tier mid-range graphics cards can only use the PCI Express x16 slot to draw their power from, but more demanding ones will need to use a 6-pin or 8-pin PCI Express power connectors. It can be especially confusing when using a multi-GPU setup, like with the SLI. In that case, the power requirement is the sum of two (or more) connected graphics cards.

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PCI Express x16 Connector

PCIe Express x16 Connector - GPU Connector

Motherboards come with the aforementioned PCI Express x16 slot that can provide a maximum of 75 watts of power. Some come with multiple PCI Express x16 slots in order to connect more GPUs, but like it’s already been stated, this increases the required power.

6-Pin Connector

PCI Express x16 - 6 Pin Connector
A 6-pin connector

This connector can supply the GPU with an additional 75 watts of energy. What this means is that the graphics card will use both PCI Express x16 slot and also draw power directly from the PSU (Power Supply Unit).

Despite 150 watts being enough for most graphics cards, cards like Nvidia’s RTX 2080 require upwards of 220 watts and system power of 650 watts. Seeing how 150 watts will be enough for most mid-range cards, it is them that usually come with the 6-pin power connector.

The terms “PCI Express cables” or “PEG cables” (for PCI Express Graphics) can also be used to describe 6-pin connectors.

8-Pin Connector

8-Pin Connector
An 8-pin connector

Although the math doesn’t seem right when compared to the 6-pin connector, the 8-pin connector can deliver 150 watts to the graphics card. If the GPU requires more than 150 watts then it will by design come with an 8-pin connector or two 6-pin connectors.

As always, there are outliers. The most power-hungry graphics cards will come with a 6-pin and an 8-pin connector. For example, Nvidia’s GeForce GTX 1080 Ti has both types of connectors and thus has a maximum power consumption of 250 watts.

There are even some outlandish situations where the GPU will have two 8-pin connectors. So, by simply adding all the numbers together we get to a total of 375 watts, but that is truly an extreme case. On top of that, there’s still a need to power the CPU (that is another big energy spender) and the rest of the components.

It’s safe to say that your machine will be properly powered with a decent 650 watts PSU although if you’re building a gaming rig and want to future proof it (which, let’s be honest, is next to impossible) you can get a more powerful PSU. But, be careful because with great power comes a greater risk of overheating. There is also a rule of thumb that the PSU runs best when it’s at 50% capacity, but that is a different topic that should really be looked at on a per-case basis.

Adapters Or Converters For Connectors

There are often compatibility issues when building a PC and power connectors are no different. Luckily, the computers are made by engineers who like to adapt stuff that’s not fitted to their needs by default.

A company by the name of Molex pioneered these pin connectors all the way back in the late 50s and early 60s and have become synonymous with the term. So don’t be surprised to hear these referred to as Molex Adapters or Molex Converters.

4-Pin Molex to 6-Pin PCI-E Adapter Cable

You’ll use this one if your graphics card requires a 6-pin power connector, but your PSU doesn’t have it. This is also interesting case as that’ll be a sign of a very old PSU, so maybe there’s a time for upgrade. If you’ll still stick to your guns, know that this sort of an adapter can sometimes require one 4-pin connector, but it’ll most often be two which is the recommended option.

4-Pin Molex to 8-Pin PCI-E Power Adapter Cable

This one uses two 4-pin connectors and adapts it into an 8-pin connector. 4-pin to 8-pin is something that will likely be the most useful with upper mid-range and high-end graphics cards.

6-Pin to 8-Pin PCI-E Adapter Cable

If you recently purchased a top-class GPU, it’ll likely require an 8-pin connector which some PSUs might not have. In that case, the 6-pin to 8-pin adapter is the solution for you.

SATA to 6-Pin PCI-E Adapter Cable

What this one does is convert your SATA connectors to a 6-pin one, but this is generally advised against. It is possible that SATA won’t be able to handle the power that your graphics card may require and this situation is not something that you want to be in the middle of, especially if the cable is labeled as “SATA only”.

SATA to 8-Pin PCI-E Adapter Cable

Likewise, SATA can also be adapted into an 8-pin power connector. In this particular scenario, there will be two SATA connectors for one 8-pin connector.

Important Note About Adapters

In most cases, it’ll be best to upgrade your PSU if you lack connectors as it’s possible that they weren’t built with your power consumption in mind. Another very important thing regarding SATA to Molex adapters. If possible, it’s best to use Molex to Molex for your GPU needs as they have thicker wires and can provide more current. A SATA to Molex adapter might be exposed and lead to burnout if the GPU draws more power with a higher load or by overclocking.

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Aleksandar Cosic

Alex is a Computer Science student and a former game designer. That has enabled him to develop skills in critical thinking and fair analysis. As a CS student, Aleksandar has very in-depth technical knowledge about computers, and he also likes to stay current with new technologies.