How do I supply power to a PCIe x16 to x8x8 bifurcation card?

Posted by d00m_sayer@reddit | LocalLLaMA | View on Reddit | 7 comments

I've been seeing PCIe x16 to x8x8 bifurcation cards mentioned a lot and I'm considering getting one, but I'm stuck on how to power it correctly and safely. The specific card I'm looking at requires an external power connector for its 150W rating, but the port looks like a 4-pin CPU/EPS connector, which is already in use for my CPU. I'm hesitant to use potentially hazardous solutions like cheap Molex adapters or a risky second PSU (even with the same type) setup that could fry my components. Could someone please clarify if I am misidentifying this connector, what the standard and safe method for powering these cards is, and what the recommended solution would be if my current PSU doesn't have the right spare cables?

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7 Comments

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droptableadventures@reddit

Can you post a link or picture of what your bifurcation card looks like, and tell us which PSU you have?

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segmond@reddit

They often take a molex or 6 pin power. Some of them take a sata power cable, avoid those and go with molex or 6 pin. What does "cheap molex adapters" even mean? The PCI slot specs calls for 75watts. When you split a physical slot, then you now have 2 slots that need 150watts, but only 75 is going in, so you need auxiliary power to bump it up. There's nothing risky about a second PSU, you use an automatic sync card to keep multiple PSUs powered. I have done 4 at a time.

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DataGOGO@reddit

Normally they use a 6 / 8 pin pci-e connector

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ArtisticKey4324@reddit

You don’t have any free molex? The bifurcation cards usually come with the adapter included so dw. Source: bought two, one off eBay one Amazon, both of them did

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Nerosephiroth@reddit

If you're feeling adventurous and you have soldering ability, 12v is yellow, red is 5v, black is ground. Usual caveat, don't do it if you don't know how. Them pixies are constantly pissed off. But back in the day, this is how I powered devices I didn't have the cable for. You can even buy the crimping set and molex male connector to make it fancy. Instead of how we did with solder, electrical tape, and hope.

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Secure_Reflection409@reddit

Just buy a bigger psu.

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DeltaSqueezer@reddit

You can buy adapters which take input 2 PCIe power cables and output 12v EPS.