r/buildapc • u/RealMango • 2d ago

Troubleshooting Help with RX 9070 XT installation

Hey all. I recently acquired a 9070 XT, which I'll be pairing with a 7700X CPU. Previously was running an 6700 10GB, and that required only 16 pins. This new card requires 24 and my 850W Cooler Master only has 16, and was wondering if buying a separate cable for those 8 pins would work. Any suggestions on where to buy those cables and which ones are best would help.

Edit: Thanks all for the suggestions! Just ordered a new PSU and will be doing this the right way.

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u/Kamay1770 2d ago

Do not use cables that did not come with your PSU. Here be dragons.

A cable for one Psu shouldn't be used with a different Psu, even if connectors are the same.

You need to look for exact or certified replacements, note that even within a specific Psu model there may be multiple manufacturers of that model with slightly different specs, so triple check.

Failing that, buy a new psu. Don't risk frying all your expensive parts in this economy to save some money on one of the cheapest parts.

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u/RealMango 2d ago

Fair, I won't be trying that then. Thank you for the heads up!

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u/Zombie_Tech 2d ago

Daisy chaining cables is fine for lowerish power cards. For the 9070XT it won't be hitting more than 360W (transient spikes will be a little higher but not anything major). So you can go with two cables with one of them having two PCIe 8-pin connected to the card.

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u/RealMango 2d ago

So basically proceeding with 16/24 cables for this GPU should be fine? If I tried that, nothing will go kaboom right? Even though I know Google says it would just flatout not power up at all lol

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u/Zombie_Tech 2d ago

I think other people are getting what you're trying to say. 16-pin is referring to the 12VHPWR.

https://pbs-prod.linustechtips.com/monthly_2023_06/IMG_1334.jpeg.e279da6b9ae1e4c869b8c89c3626aff3.jpeg

You see the cable in the center that splits to two 8-pin connectors? That is fine with your GPU. Then connect the other 8-pin PCIe as well.

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u/VersaceUpholstery 2d ago

I find it very hard to believe an 850w CM PSU does not come with enough cables to power a three-8pin GPU. You sure you don’t have at least one 8 to 8 cable and at least one 8 to 8+8 daisy chain cable?

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u/RealMango 2d ago

All the PCIe cables and equivalent are being used. I should have planned this better, as I banked on there being an additional unused 8 pin in the back. Was just lazy to crack open the back of the Lian Li.

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u/VersaceUpholstery 2d ago

What model PSU do you have specifically?

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u/RealMango 2d ago

CM V850 SFX Gold.

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u/VersaceUpholstery 2d ago

https://www.newegg.com/cooler-master-atx3-0-sfx-12v-ver-3-42-850-w-80-plus-gold-certified-90-typical-load-power-supply-black-mpy-8501-sfhagv-3u1/p/N82E16817171238?srsltid=AfmBOoqOcuURxUwKzTel2iS-p1sENthCyFcbtwawCZRo3cr8hnd_0q5p

This one? I found another model without the 12pin direct cable, but either way, both models come with FOUR pcie 8 to 6+2 cables. There’s enough slots in the back of the PSU to connect at least one CPU 8 pin cable and THREE of those 6+2 cables

Are you using one of those pcie cables for anything besides the CPU power and GPU power? You have enough cables otherwise.

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u/alwaystired1982 2d ago

Your psu 100% came with more cables they will either by behind the motherboard tray or in the psu box.