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Re: Follow the specs :) (was Re: AMD GPU hard lockups)



On 8/2/23 19:30, zithro wrote:
On 02 Aug 2023 23:29, Celejar wrote:
 > But reputable companies do produce 6-8 pin adapters, e.g.:
[...]
 > (I just ordered the Cable Matters one.)

Out of curiosity, I checked the links.
Funny that "reputable companies" (I'm not attacking you, but them) don't even specify the max power rating as product specs, and when specified, it's only in users Q&A ... You also have to dig deep to get the wires size in AWG (ie: zoom on pictures ...) !
Compare that to the information you get for the PSU and the GPU !

Anyways :
1st link: "The maximum power rating for the PCIEX68ADAP is 75W"
2nd link: "Max Power Rating 150W"
3rd link: (nowhere to be found, at least quickly)

1 and 2 use AWG18 wires, and on 3 they look even thinner (can't really tell as the pic is s***).
I'd eliminate the 3 from the start. No specs, no money.
And either 1 or 2 is lying : same AWG, different power rating (ok, the wire style is precised nowhere : single core, threaded, etc). But we can safely assume that 150W @12V is not possible : 12.5A is out of specs. (Try "https://www.engineeringtoolbox.com/wire-gauges-d_419.html"; for more info on AWG, and use the formula Watts = Volts x Amperes).

On 02 Aug 2023 23:37, piorunz wrote:
Your GPU max TDP is 150W, meaning it will draw 75W from PCI-E slot and
75W from 8-pin cable.

So the wires will work around their limits.
One little power spike and kaboom.
Fire, exclamation mark ; fire, exclamation mark.
Joke aside, the fire hazard is real. Especially exceeding limits with low-end products, when you don't know if the materials are fire-proofed.

Your 8-pin adapter must have been very poor quality. I don't know what
kind of adapter it was, but adapters which make 8-pin from 6-pin, are
dangerous. Better to use 2x 6-pin -> 1x 8-pin adapter to correctly
assign wires to each corresponding pin.

Separate the men from the boys, and ask the vender what the ampacity of the wire used in their product is rated at. If they cannot answer that, put our card away and go someplace that knows.

That is a term used in the NEC, and represents the maximum current the wire can handle. AWG 10 gauge copper has an ampacity rating of 20 amps, so its sick bird to feed it with a breaker rated for more than 20 amps. 12 gauge is 15 amps, By the time you get to 18 gauge it close to an amp or two.

I agree, so that each wire (or group of wires) does not exceed the max current it can draw.

I found two pages cleanly explaining this, both were worth a read.
But don't quickly jump to conclusions, follow the flow !

https://www.cgdirector.com/gpu-power-cable-guide/
https://www.pcworld.com/article/395059/one-cable-or-two-for-powering-a-graphics-card-heres-the-answer.html



Cheers, Gene Heskett.
--
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 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
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 - Louis D. Brandeis
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