GPU Power Connectors Explained. What power cable for gpu

– Rated current: up to 9 A per connector in 2 circuits, up to 8 A per connector in 3 circuits (https://www.molex.com/pdm_docs/ps/PS-45558-001-001.pdf)

How Many PCIe Cables Do I Need? – Power Cables Explained

Basically, you need as many PCIe cables as your graphics card needs. Depending on the GPU, this could mean a single 6-pin cable up to 3 x 8-pin cables on high-performance cards such as the NVIDIA RTX 3090.

Basically, PCIe components need to be powered just like any other component on a motherboard. Usually for smaller and weaker cards their power comes from the PCIe slot itself. However, some components, especially graphics cards, require significantly more power than average add-on cards such as network card, SATA expansion card or video capture cards, etc.

As such, it’s a good idea to measure how many PCIe cables I need before deciding which power supply to purchase for you. PCIe power cables are not shipped with graphics cards. Instead, they come with power supplies.

Often you will hear complaints about a non-working graphics card or even a lack of initialization. It is often a question of power.

You also often hear people asking if all the pins on the graphics cards need to be connected. The answer to that question is: YES! You must have all pins connected for the graphics card to work.

If your graphics card requires 2 x 8 PIN. Then, well, you have to provide him with 2 x 8-pin PCIe cables coming out of the power supply.

Let’s explore this topic a bit further below.

How Many PCIe Cables Do I Need?

The actual number of PCIe cables needed depends primarily on the type and number of graphics cards installed.

For example, some graphics cards, such as the NVIDIA GT 710, do not require a PCIe cable at all. This weak graphics card is powered by the PCIe slot itself.

Ranging from medium to high to extreme range, you can find cards that require as low as a single 6-pin PCIe cable, up to 3-pin 8-pin cables like the NVIDIA RTX 3090.

If you have two NVIDIA RTX cards, NVIDIA 3090 cards installed, you will need 6 x 8 pin cables.

Other popular expansion cards, such as video capture card, network card, sound card, USB hub, etc., do not require a PCIe cable.

Visual Guide for PCIe Cables and Connectors

The above graphics card requires 2 x 6 pins.

However, when looking at my power supply, I can see that it has 2 x 6 + 2 PCIe cable connectors:

6 + 2 Pin PCIe cable, has one large 6-pin connector as well as an additional 2-pin split in case you need more power. Basically a single 6 + 2 pin cable can power the 8 pin socket on the graphics card.

However, the graphics card I have does not have a dedicated 8 pin connector. Instead, it requires two separate 6-pin PCIe cables. Therefore, the additional 2 pins will be useless in this case and will not be used.

Here you can see that both the PCIe cables available to me from the power supply are connected to the graphics card. However, both cables have 2 unused pins.

You must have the entire pin attached to the GRAPHIC CARD.

There is also a rule of thumb that a power supply works best at 50% capacity, but that is a different topic that should be considered on a case-by-case basis.

PCI Express x16 Connector

Motherboards are equipped with the aforementioned PCI Express x16 slot, which can provide a maximum of 75 watts of power. Some have multiple PCI Express x16 slots in order to connect more GPUs, but as mentioned earlier this increases the power requirement.

Here are some examples of GPUs that do not require an external power supply: GT 1030, GTX 1050 2GB variant, RX 550, RX 460 and many more. Since neither of these GPUs have a lot of processing power, they don’t need more than 75 watts of power.

6-Pin Connector

This connector can provide an additional 75 watts of power to the GPU. This means that the graphics card will use the PCI Express x16 slot, as well as draw power directly from the Power Supply Unit).

Despite the fact that 150 watts is sufficient for most graphics cards, high-end cards like the NVIDIA RTX 3080 require over 320 watts and a system power of 750 watts. Since 150 watts is enough for most mid-range cards, they typically come with a 6-pin power connector.

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

With all your cables connected, you also want to finish the extra tidying up of your cables wherever you can, such as simply tying them up with a zipper or cable ties (well, you don’t have to, but it’s perfect, and it’s not that hard).

Nvidia Geforce RTX 3070 Founders Edition card	Nvidia Geforce RTX 3080 Edition for founders	Nvidia Geforce RTX 3090 Founders Edition card
One 8-pin PCIe power cable (1x PCIe 8-pin)	Two 8-pin PCIe power cables (2x PCIe 8-pin)	Two 8-pin PCIe power cables (2x PCIe 8-pin)
GPU power: 220 W	320W	350W
System power required: 650W	750W	750W

GeForce RTX 3090 GAMING X TRIO 24G	GeForce RTX 3090 VENTUS 3X 24G	GeForce RTX 3080 GAMING X TRIO 10G	GeForce RTX 3070 GAMING TRIO	GeForce RTX 3070 VENTUS 2X
3x PCIe 8-pin	2x PCIe 8-pin	3x PCIe 8-pin	2x PCIe 8-pin	2x PCIe 8-pin
GPU power: 370 W	350W	340W	TBD	TBD
System power required: 750W	750W	750W	TBD	TBD

ROG Strix GeForce RTX 3090 24G Gaming	ROG Strix GeForce RTX 3080 10G Gaming	ROG Strix GeForce RTX 3070 8G Gaming	DUAL RTX 3070 8G
3x PCIe 8-pin	3x PCIe 8-pin	2x PCIe 8-pin	2x PCIe 8-pin
GPU Power: None	Not reported	Not reported	Not reported
System power required: 850W	850W	750W	750W

EVGA GeForce RTX 3090 XC3 GAMING	EVGA GeForce RTX 3090 FTW3 GAMING	EVGA GeForce RTX 3080 XC3 GAMING	EVGA GeForce RTX 3080 FTW3 GAMING
2x PCIe 8-pin	3x PCIe 8-pin	2x PCIe 8-pin	3x PCIe 8-pin
GPU power: 350 W	350W	320W	320W
750W	750W	750W	750W

GIGABYTE

AORUS GeForce RTX 3090 XTREME 24G	GeForce RTX 3090 GAMING OC 24G	AORUS GeForce RTX 3080 XTREME 10G	GeForce RTX 3080 GAMING OC 10G	GeForce RTX 3070 EAGLE 8G
3x PCIe 8-pin	2x PCIe 8-pin	3x PCIe 8-pin	2x PCIe 8-pin	2x PCIe 8-pin
Not reported	Not reported	Not reported	Not reported	Not reported
System power required: 850W	750W	750W	750W	650W

So you’ve got it. Nothing too crazy, but still three 8-pin cables for one graphics card can be a bit larger than the ones the average computer builder is used to. Before installing the card, make sure you have the necessary power supply cables handy. Especially for NVIDIA Founders Edition cards, the company also supplies a 12-pin adapter that can be used to make plugging the card a little easier for power.

For more information on choosing a new power supply for your design, read our guide to power supplies .

All GPU power connectors can be difficult to understand. Here is a simple explanation of the 6-pin and 8-pin connectors and their differences.

What are the Types of Cables and Connections Used by Graphics Cards?

There are various connectors and cables that graphics cards need to connect to a computer.

1. PCIe slot
2. PCIe power cable
3. Video output cables

1. PCI Express x16 Connection

PCI Express x16 connection is the most popular and widely used method of connecting graphics cards.

PCI Express x16 can transfer up to 75 watts of power to the graphics card. If your graphics card needs less than 75 watts to run, you can simply plug it into the PCI Express slot on your motherboard and you’re done.

The MSI GeForce GTX 750 Ti is a low-end graphics card that only requires 60 watts to run.

Therefore, it does not require a PCIe power cable. PCI-E express can meet your power requirement by itself.

2. PCIe Power Cables

For graphics cards that require more than 75 watts of power, the PCIe power cable is used to connect the graphics card to the power supply as shown below:

6-Pin PCI-E Connector

If your card needs more power to function, it will use either a 6-pin or an 8-pin connector. The 6-pin connector can provide your card with an additional 75 watts of power.

The Asus ROG Strix GeForce GTX 1650 OC edition 4GB GDDR6 is a good example of a card that only requires one 6-pin PCI-E cable to function.

The ASUS ROG Strix GTX 1650 actually has a power requirement of around 100 watts. However, with a PCIe slot providing 75 watts, the rest of the power must come from the power supply.

Note that in this case, an additional 6-pin connector will provide around 25 watts of power, even though it may provide 75 watts of extra power.

8-pin PCI-E Connector

For cards that require even more than 150 watts of power to function, you will need to use an 8-pin PCI-E cable. The 8-pin cable can transfer up to 150 watts of extra power.

The XFX Radeon RX 580 GTS is a graphics card that requires one 8-pin cable to connect to the power supply.

Combination of 6+6 Pin, 6+8 Pin, 8+8 Pin and MORE Connectors

For graphics cards that require more power, a combination of the two connectors may be required.

An example of such cards is the SAPPHIRE NITRO + RX 580. This card requires both a 6-pin and an 8-pin cable to be connected to the power supply.

Likewise, there are cards that may even require 3 x 8-pin connectors, such as the ASUS ROG-STRIX-RTX3080-10G-GAMING

Cables and Graphics Card Maximum Power Consumption

The table below shows the power delivered by the type of PCIe cable and their combination.

PCIe x16 (75W)	6-pin cable (75W)	8 pin cable (150W)	12 pin cable (600W)	Maximum power Digested
75W	0	0	0	75W
75W	1x75W	0	0	150W
75W	0	1x150W	0	225W
75W	2x75W	0	0	225W
75W	1x75W	1x150W	0	300W
75W	0	2x150W	0	375W
75W	1×75	2x150W	0	450W
75W	0	3x150W	0	525W
75W	0	0	1x600W	675W

Most modern motherboards require the full 8 pins to be plugged in, but some may only need 4, in which case one of the two 4 pin headers will suffice. Align the pins carefully, hold the motherboard for better control, and push the cable nicely and firmly into place.

Riser Card GPU Power Cable 6 plus 2 & 6 pin connectors 7920 Rack

This product has been tested and approved for use with Dell ™ systems to ensure that it will work with your computer. It is supported by Dell ™ Technical Support when used with a Dell system.

This product has been tested and approved for use with Dell ™ systems to ensure that it will work with your computer. It is supported by Dell ™ Technical Support when used with a Dell system.

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Most modern motherboards require the full 8 pins to be plugged in, but some may only need 4, in which case one of the two 4 pin headers will suffice. Align the pins carefully, hold the motherboard for better control, and push the cable nicely and firmly into place.

How much power can each PSU cable safely supply?

Putting it all together:

I’m glad you asked. Here are the specifications of the above using publicly available sources. If you want to delve as much as I do, I strongly encourage you to purchase copies of Dr. Albert Malvino’s Electronic Principles and Roger Tokheim’s Digital Electronics: Principles and Applications.

– Rated current: up to 9 A per connector in 2 circuits, up to 8 A per connector in 3 circuits (https://www.molex.com/pdm_docs/ps/PS-45558-001-001.pdf)

– Assuming: variable load, constant run time, insulated / insulated wire, wire insulation temperature 105 ° C, circumference less than 6 feet, max. 3% voltage drop, up to 30 ° C ambient

(* most likely 3 circuits, but confirm with mfg power supply or multimeter that 3 pins are + 12V, 3 pins are grounded)

As always, I hope this helps clear up some confusion and prevent the overloaded components from catching fire. Let’s be responsible for it!

As mentioned, the most important expansion card that uses PCIe power cables is the graphics card, as many mid- and high-range graphics cards draw significantly more power than the 75W provided by the PCIe X16 slot alone.

Connect 4 Pin Molex Power Cables (Optional)

Molex connectors have been almost completely replaced with SATA connectors, however some power supplies still have them and you may still need to use them with accessories such as some liquid coolers for processors or case fans. These are 4 pin connectors that look like this: (and may be labeled “peripheral” cables in the power supply specification)

Molex power connectors may be required for some accessories

For example, for our sample PC kit used in our complete PC building tutorial, since we can’t connect our case fans directly to our motherboard because we only have one fan header on the board, we’ll connect the case fans to the Molex connector of our power supply.

go ahead and plug in the case fans if that applies to you, although your best bet would be to hook the case fans into the motherboard fan headers. The downside to connecting the case fans directly to the PSU is that you have no control over them, and they will always work 100%.

The ability to connect the fans directly to your motherboard (if your motherboard supports it) allows you to use software to control the speed of the fans. You probably don’t need to worry about it, but it’s worth keeping in mind. Sometimes fans can be louder than you want and you’ll want to tweak their settings.

If you don’t need Molex connectors and you’re using a modular power supply, just keep them in the power supply packaging, otherwise you will have to hide them somewhere. Another thing I’m going to say about Molex connectors is that sometimes they need real, REAL strong pressure to connect them properly, so don’t be afraid to use a little bit of force with these dudes.

Finishing Off With More Cable Management Tips

After connecting the necessary cables, you’ll want to hide the unused cables of the non-modular power supply somewhere in your housing

As explained earlier, when connecting the power cables to your computer you want to pull each cable through the openings in the case and / or behind the motherboard area wherever possible to keep everything nice and tidy.

In other words, you don’t want to just plug the cable into the back of the PSU and then just go directly to the component you are plugging in and plug it in; if you do this you will have loose cables everywhere that will stick out which will be ugly but also once can be cumbersome to work with (and which can collect dust faster and easier and even damage something if a loose cable comes into contact with something like this like a fan).

With all your cables connected, you also want to finish the extra tidying up of your cables wherever you can, such as simply tying them up with a zipper or cable ties (well, you don’t have to, but it’s perfect, and it’s not that hard).

Why cable management?

It’s a good idea to do this even if you don’t have a transparent case that exposes internal components, as cable management serves not only aesthetics but also practicality and extending the life of your PC (by maximizing airflow, reducing dust build-up, and avoiding loose cables potentially damaging other parts).

The amount of cable management you do once the system is connected to each other will depend on your version and how much you care about the new system. The truth is, some budding builders will just throw in (or won’t do at all) and no one is forcing you to manage your cables. A dirty build isn’t the end of the world, but we recommend taking the time to clean up everything to the best of your ability now. It doesn’t have to be long, and the simple 30 minutes to an hour of cable tidying up could be worth it for a new system in the long run.

Cable management of a non-modular power supply

If you have a modular PSU, cable management will be easier as you have fewer cables for tidy management. If you have a non-modular power supply like the one we installed for our example, compile in this tutorial and also thread through all the cables you plug into the back of the case first you want to hide the cables you didn’t plugged in (the ones still connected to the power supply) nice and neat inside the case somewhere, for example under the cage / each hard drive, which we will do in our compilation.

Avoid the clusters of doom cables

In addition to managing 101 cables, which we explained earlier in this guide, which is mainly about pulling cables through any available holes in your case, you also want to use cable / twist ties to tie any stray cables (or groups of cables) together in the same direction and place them on the side panel. You want to avoid large bumps / cable clumps in your system. Some cases go a step further and have quick-release cable ties and small tabs built into the back of the case to which you can conveniently attach cables.

Just do everything you can

Be aware of airflow when managing your cables, and try not to cover your case fans or fans with cables, if possible. If your case doesn’t have too many cable management options, don’t worry too much but try to be content with what you have.