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Nvidia's RTX 5090 power connectors are melting

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Re: Nvidia's RTX 5090 power connectors are melting

#341

Post by tass »

colejohnson66 wrote: post #232
anankaie wrote: post #188

Earlier quoted context omitted.

I did not realize the outlet impacts the amperage… Is it a rating issue, or is there an actual part there that will trip?

The outlet itself doesn't care, but the shape of the receptacle is supposed to restrict insertion of a 20 amp device into a 15 amp socket. You can stick a 15 amp device into a 20 amp socket, but not vice versa. The electrician should be installing 20 amp sockets if the cabling can support it, but many don't. It's the difference between NEMA 5-15 and 5-20: https://en.wikipedia.org/wiki/NEMA_connector#NEMA_5

> The electrician should be installing 20 amp sockets if the cabling can support it, but many don't.

I think this is mainly because the 20 amp outlets are kind of ugly, and the fact that barely anything actually uses a 20 amp plug.

In my house, almost every circuit has a 20 amp breaker and 12 ga (yellow) romex, but only a couple of outlets are 5-20.

Re: Nvidia's RTX 5090 power connectors are melting

#342

Post by m463 »

rincebrain wrote: post #321
Ygg2 wrote: post #307

Earlier quoted context omitted.

No sane individual is going to buy 5090 for $2000-100000 and hook it up to a $15 Power supply.

Correct, but it turns out, a fair fraction of the people who day 1 purchase a GPU for that much may not necessarily be described as wholly sane.

your comment makes me wonder...

Is it a computer science type person, who might be unaware of electrical engineering...

Or someone who takes a perfectly good car and adds ridiculous rims that rub?

Re: Nvidia's RTX 5090 power connectors are melting

#343

Post by DannyBee »

quickthrowman wrote: post #333
superjan wrote: post #266

Earlier quoted context omitted.

When you work with normal AC power, it is considered unsafe practice to use parallel wires to share load in a circuit. Reason: one might get decoupled somehow, you don’t notice, and when fully loaded the heat causes a fire risk. This problem sounds similar. A single fat wire is the easiest, but I guess it’s not that simple.

> When you work with normal AC power, it is considered unsafe practice to use parallel wires to share load in a circuit. The NEC permits using conductors #1/0AWG or larger for parallel runs, it doesn’t forbid it entirely.

Yeah. I have 800 amp service which is basically always done with parallel 400 mcm or 500 mcm (depending on where it is coming from, since POCO doesn't have to follow NEC)

Within conduit, there is basically no other option. In free air there are options (750 mcm, etc).

Even if there were, you could not pay me to try to fish 750 mcm through conduit or bend it

Re: Nvidia's RTX 5090 power connectors are melting

#344

Post by tcdent »

zamalek wrote: post #296
tcdent wrote: post #285

Earlier quoted context omitted.

This is the most informative assessment in this thread. You'd expect to see the capacity to be 125% as is common in other electrical systems. Ratings for connectors and conductors comes with a temperature spec as well, indicating the intended operating temperature at a load. I'm sure, with this spec being near the limit of the components already, that the operating temperatures near full load are not far from the lim…

"3rD party connectors" is being waved around by armchair critics. The connectors on the receiving end of all of this aren't some cheap knock-off, they are from a reputable manufacturer and probably exceed the baseline.

Show me the Molex logo molded on that connector end and I'll believe you.

It's all off-brand slop from companies that learned marketing by emulating western brands. Kids on the internet lap up circuitous threads about one brand being better than the other based on volume.

"MODDIY" is a reputable brand? C'mon.

Re: Nvidia's RTX 5090 power connectors are melting

#345

Post by clhodapp »

zamalek wrote: post #296
tcdent wrote: post #285

Earlier quoted context omitted.

This is the most informative assessment in this thread. You'd expect to see the capacity to be 125% as is common in other electrical systems. Ratings for connectors and conductors comes with a temperature spec as well, indicating the intended operating temperature at a load. I'm sure, with this spec being near the limit of the components already, that the operating temperatures near full load are not far from the lim…

"3rD party connectors" is being waved around by armchair critics. The connectors on the receiving end of all of this aren't some cheap knock-off, they are from a reputable manufacturer and probably exceed the baseline.

The cable must necessarily be third-party from the perspective of the GPU or from the perspective of the power supply.

If it's built to the expected tolerance, it should work.

Re: Nvidia's RTX 5090 power connectors are melting

#346

Post by rangestransform »

nvarsj wrote: post #302

I would love to get some insight from Nvidia engineers on what happened here. The 3 series and before were overbuilt in their power delivery system. How did we get from that to the 1 shunt resistor, incredibly dangerous fire-hazard design of the 5 series? [1] Even after the obvious problems with 4 series, Nvidia actually doubled down and made it _worse_! The level of incompetence here is actually astounding to me. Nv…

Not sure if this is related but a friend there said a lot of people retired

Re: Nvidia's RTX 5090 power connectors are melting

#347

Post by deelowe »

mjevans wrote: post #305
zamalek wrote: post #290

Earlier quoted context omitted.

> Any imbalance I watched de-Bauer's analysis this morning, and you've seemingly hit the nail on the head. Even on his test bench it looks like only two of the wires are carrying all of the power (instead of all of them, I think 4 would be nominal?) - using a thermal camera as a measuring tool. The melted specimen also has a melted wire. Maybe 24V or 48V should be considered, and higher gauge wires - yes.

It would be _lovely_ if instead of the 12V only spec we went to 48V for internal distribution. Though that would require an ecosystem shift. USB-PD 2.0~3.0 would also be better supported https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver... As others no doubt mention Power (loss, Watts) = I (amsp) * V (volts (delta~change on the wire)). dV = I*R ==> dV = I * I / R -- That is, other things being equal, amps…

48v is basically already the standard for hyperscalers with power shelf rack designs.

Re: Nvidia's RTX 5090 power connectors are melting

#348

Post by jffry »

ddalex wrote: post #165
xg15 wrote: post #162

At this point, I'm waiting for the first RTX generation that just comes with its own separate PSU and wall plug cable.

People are hooking air con units to liquid GPU coolers https://www.tomshardware.com/pc-components/liquid-cooling/rt...

For what it's worth, the "air conditioner" is just a giant radiator. From the linked bilibili video it's clear (at 1:20 mark) that they've repurposed the radiator, fan, and case from an air conditioner but there is no compressor.

Re: Nvidia's RTX 5090 power connectors are melting

#349

Post by albrewer »

ddalex wrote: post #165
xg15 wrote: post #162

At this point, I'm waiting for the first RTX generation that just comes with its own separate PSU and wall plug cable.

People are hooking air con units to liquid GPU coolers https://www.tomshardware.com/pc-components/liquid-cooling/rt...

I've read about this exact practice in one form or another since the Pentium 3 (sometimes just directly cooling with R134).

Re: Nvidia's RTX 5090 power connectors are melting

#350

Post by MBCook »

nvarsj wrote: post #302

I would love to get some insight from Nvidia engineers on what happened here. The 3 series and before were overbuilt in their power delivery system. How did we get from that to the 1 shunt resistor, incredibly dangerous fire-hazard design of the 5 series? [1] Even after the obvious problems with 4 series, Nvidia actually doubled down and made it _worse_! The level of incompetence here is actually astounding to me. Nv…

Maybe having cards drawing >500/600 watts is just a bad idea.

Add in a CPU and such and we’re quickly approaching the maximum amount of power that can be drawn from a standard 12 amp circuit continuously.

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