Are CPU and GPU cables the same?

Nearly a decade ago, even the best CPUs didn’t require any dedicated power connections. All the necessary power to the CPU was supplied through the huge 12-pin motherboard connector. But as processors have gotten power-hungry and clock speeds started going beyond 4GHz, a dedicated power connector to sustain boost clock speeds became important. Today, the best gaming CPUs need up to 16-pin power connections to work at 100%. You can use the best thermal paste on your CPU, but if its power requirements aren’t fulfilled, your processor will throttle. And even though CPU and GPU cables look the same, using GPU cables to power your processor is not the way to do it.

Why do CPU and GPU cables look the same?

A CPU cable is usually called an EPS cable, whereas the GPU uses a PCIe cable. A standard PCIe cable has six pins, whereas a standard EPS cable has only four pins. They often have additional pins for extra power. A 6-pin PCIe cable has a dangling 2-pin connecter, which you can attach to the main 6-pin connector to create a 6+2 pin connector, giving a total of eight pins. Similarly, a 4-pin EPS connector has an accessory 4-pin connector dangling, which you can join to create a 4+4 pin connector for the CPU for eight total. Both the 6+2 pin and 4+4 pin connectors look identical and can cause confusion among new PC builders.

How are both cables different?

Both these cables have differently shaped connectors. Normally, you can’t fit the EPS cable into the PCIe connector on your graphics card, and vice versa. The power supply manufacturers created this distinction to prevent people from accidentally using the wrong cable in the wrong connector, as it could be detrimental to your PC components.

Additionally, the power requirements of both the CPU and GPU are vastly different. While both these cables carry the same voltage (12V), your CPU doesn’t need as much power as your GPU does, mainly because the latter has a lot more cores than a CPU. Plus, unlike the GPU, the fans on your CPU’s heatsink have separate cables and connections and receive power directly from the motherboard. Hence, a PCIe cable carries more power and current than an EPS cable.

What happens if you use the wrong cables?

It’s not uncommon for new PC builders to confuse the EPS and PCIe cables, especially when using 6+2 PCIe and 4+4 EPS connectors, as both look identical. But the most important thing to remember is that you can’t use the PCIe cable for the CPU or the EPS cable to power the GPU, as the connectors for both are different, and the cables won’t fit.

Even if you manage to force the cables into the wrong connectors, your PC won’t turn on. This is because both the cables carry current in the opposite connectors; the EPS cable has current in the four connectors close to the clip, and the PCIe cable carries current in the four connectors away from the clip. Plugging the cable into the wrong connector will result in a short circuit, and any good power supply should instantly shut down. But, if the worst comes to pass, you might end up frying your CPU, GPU, power supply, and even the motherboard. That’s why you should always avoid mixing and matching PSU cables.

Source: Corsair

Corsair Individually Sleeved PSU Cables Starter Kit

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The Corsair PSU cable starter kit comes with four cables: Two PCIe, one EPS, and one 24-pin ATX for the motherboard. This starter kit should solve all your problems if you are short on a PCIe or an EPS cable.