Thoughts on employing pigtail power connectors for GPUs?
Thoughts on employing pigtail power connectors for GPUs?
To clarify, I understand that employing the pigtail 6+2 on PCIe for the other power port on a GPU is not recommended. Could you explain the power output of the main 6+2 connection and how much extra power the connected tethered 6+2 cables supply? Also, my curiosity is about the current purpose of these tethered connectors and why they remain in use today.
Compatibility is the key factor behind the pigtail design. In a similar way, the CPU +12VEPS cable typically uses a 4/4 pin configuration rather than an 8-pin setup in most cases. However, some PSUs feature a power cable with a +12VEPS connector that remains an 8-pin, making it difficult to split. A 6-pin PCI-E power cable can deliver up to 75W. An 8-pin PCI-E cable, especially when equipped with a pigtail, supports up to 150W. The pigtail adds two extra grounding wires, effectively doubling the current capacity of the PCI-E power cable (from 2.083A to 4.167A) and consequently increasing its wattage output.
Additionally, the +12VHPWR connector is used with RTX 40-series GPUs; it provides 300W when paired with two 8-pin connectors for the RTX 4070, 450W with three 8-pin connectors for the RTX 4080, and 600W with four 8-pin connectors for the RTX 4090.
So then I'm not grasping the limitation. You're implying the pigtail doubles the amps and wattage, which affects voltage (V x A = W) for the 6/2 PCIe connector. But everyone says not to use it.
Excluding the use of pigtail is no longer outdated, particularly with modern PSUs and appropriate thick wires.
The pig tail is still suitable for use, although there were problems in the past. The wire was thinner and the ends weren’t as good, but now it’s been fine for years. The adapters, such as duel molex to 6 pin, are not recommended; better to opt for a higher-quality PSU rather than risking a power draw card with high consumption.
It depends on the power supply cable gauge and its length.
Refer to the PSU manual for details.
My memory seems correct—Seasonic mentioned 225 watts per cable, possibly 250 if it was a long time ago.
If the card requires an 8 and 6 pin connector and its TDP is under 225 watts with the pigtail, that should be acceptable.
Actually, on a 6+2 cable setup, those extra two pins don’t add any extra power—they’re just ground connections that inform the GPU the 6-pin can supply 150 watts. Pigtailed cables can deliver up to 300 watts, but they’re not recommended for regular use because transient spikes might exceed the cable’s rating. They’re best reserved for occasional extra power needs. If your GPU has a 3x8-pin configuration, you could use two separate 6+2 cables plus one pigtailed one. However, with a 150W limit paired to two 8-pin cables, the pigtail can still be used since the additional pin is intended for handling transients (unless you’re overclocking).