As GPUs become increasingly power-hungry, additional power connectors are required to supply power to the GPU. Unfortunately, many of us still utilize older power supplies with insufficient PCIe 6, 8, or even 12-pin connectors.
Some of you may want to experiment with other adapters and splitters to replace the lost connectors.
Some may even attempt to use a CPU cable for GPU! You’re lucky to have us have a lengthy debate about why you shouldn’t do it.
The gist of the entire discussion is that you cannot use a CPU cable for a GPU because the hole shapes and wattages are different. Instead, you can use CPU to PCIe adapters or other types available on the market instead of the CPU cable for GPU.
When powering a GPU, I strongly advise against using any form of power splitter! Especially with a GPU as power-hungry as the upcoming RTX 4000 series.
In this article, we’ll clear up any confusion about whether or not you may utilize a CPU (EPS) wire on a GPU. Shall we?
You Can’t Use CPU Cable for GPU
As you can see in this photo, The CPU power connectors are separate and different from the GPU power connectors. They are not interchangeable.
For example, if your GPU requires 3 6+2 pin PCIe connectors, you must plug them all in.
The EPS connector (CPU cable) is meant to provide power to a motherboard CPU socket, while the PCI express connector (GPU cable) provides power to a GPU.
You shouldn’t be able to swap between them because the square and rounded-off connectors are not arranged in such a way.
The top left connector on the EPS 12V is squared off, but the one on the PCIe is rounded off in the previous image.
Such distinctions exist to prevent you from connecting a PCIe connector to an EPS12V.
The power connectors differ in that, while they are both 12V (yellow) and ground (black), the row closer to the PCIe connector clip is ground, and the bottom is 12V, whereas the EPS 12V is the other way around.
Because this may cause confusion for a new user, it is worth noting that all CPU/PCI-E sockets (on a modular power supply) are similar.
One would suppose that some of them are for the CPU (12V) and the rest for PCI-E. To conform with the motherboard pin configuration, the cable swaps 12V and GND pins.
Don’t Destroy CPU
Unfortunately, it’s not true that you cannot connect a PCI-e 8-pin plug to the EPS-12V (EATX) motherboard slot.
It may be an exception with FSP PSU; however, a simple change in one male pin on the PCI-e connector allows you to misconnect your PSU.
In this photo, you’ll see PCI-e and EPS-12V FSP PSU plugs compared against the GPU PCIe socket and motherboard EPS-12V socket.
The top left GPU PCIe socket, top right PCIe plug, bottom left motherboard EPS socket, and bottom right EPS plug are all visible.
As you can see, the top right pin of the PCI-e plug is rounded, which allows it to plug into the motherboard’s EPS socket mistakenly.
This method allows one to destroy motherboard/CPU components easily. I’m not sure whether this is the only PSU with this problem; I’ve never seen a Corsair PSU with a PCIe plug with a rounded top right pin.
You Can’t Even Rely on Color
Some cables are completely black, especially those that come with a cosmetics power supply, while others are all yellow. In any case, you can’t rely on the hue.
- You can’t connect male EPS-12V to female PCI-E 8-pin because one male pin of EPS is square and rounded on PCI-E.
- You can’t connect male PCI-E 8-pin to EPS-12V because two male pins on PCI-E have the top edge connected together, and the corresponding pins on PCI-E don’t have a slit for that.
CPU Cable Explained
The CPU is one of the few components of your PC that need additional electricity in addition to the power supplied by your motherboard. The CPU connection is ready to help.
The CPU connector is usually located near the CPU socket on your computer. After you’ve finished with your motherboard connector, simply plug it in and you’re ready to go.
Depending on the PC, this connector may be different. For example, in lower-end PCs, you’ll find a 4-pin connector on your motherboard, which should provide enough electricity for those lower-end chips.
Instead, an 8-pin connector can be found on mid-range and high-end CPUs, providing ample power to practically every chip.
Your PC’s power supply will almost always have an 8-pin connector that splits in two, known as a 4+4-pin. This allows it to be linked to both 4-pin and 8-pin connectors; simply set one aside if not in use.
There may be more than one CPU cable in some power supplies. Similarly, some motherboards may feature an 8-pin and a 4-pin connector, or they may only include a 12-pin connector.
While that is not the norm, some computers require a lot of CPU power, especially for those who enjoy overclocking.
GPU Cable Explained
Technically, the motherboard connector already meets all PCI Express power requirements.
After all, putting anything like a Wi-Fi card there will work flawlessly. However, some gadgets (most notably GPUs) require additional auxiliary power beyond what the motherboard offers.
PCIe cables come into play here. These are commonly referred to as GPU cables because GPUs primarily use them. They’ll be 6-pin and 8-pin connectors that sit on top of a GPU.
Depending on the GPU, you might be able to get by with just one connector, or you might need two or three, depending on the power requirements of the specific card.
If a card’s power needs are not fully met, users may encounter performance dips, instability, and frequent crashes. Fortunately, most power supplies, particularly those with larger wattages, include numerous PSU cables.
Can You Use GPU Cable for the CPU?
No, it’s impossible to use a PCI-e cable to power the CPU. Don’t even try to do it, as you may shortcircuit the whole system and also may damage the system permanently.
As we said, PCI-e cable and EPS look the same but have different power factors.
When building a desktop, you must deal with various cable types.
Various types of cable are used for different purposes as they all have different types of construction. For example, if you look at the SATA cable, it’s used for wiring the motherboard & the HDD.
But, on the other side, we have two similar-looking cables – the PCI-e 8-pin or 6+2pin and the EPS cable. They look exactly the same. You can’t see the difference if there are no markings in the cable head.
The PCI-e connector has three 12V lines and five ground lines. On the other side, you have the CPU power connector that has four 12V lines and four ground lines. Thus, there is a direct shortage of 12V.
If you try connecting the PCI-e cable in the EPS slot, you will connect a ground line in the pin of the 12V line.
So if you do this, the CPU won’t power up in most circumstances. But there’s also a chance that it’ll blast into your mouth.