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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

#491

Post by ryao »

bongodongobob wrote: post #466
lazide wrote: post #417

Earlier quoted context omitted.

They’re far faster than a stovetop most of the time, have auto shutoff so you can wander away for a minute or two or not pay attention to it and not boil off a lot of water, etc. Many parts of the world, it’s a good idea to boil water before using it for drinking, brushing teeth, etc. So it’s actually really convenient for many use cases besides tea or coffee.

That's fine, but there are no use cases in the US. If we are boiling water, it's for food, and we're doing it on the stove, just like the way everyone else cooks. In the US, there is no use case for a specialized water boiling appliance.

I have been known to heat water in a microwave after doing the calculations needed to know roughly when the water would reach boiling. It is rather quick once the microwave timer starts going.

Re: Nvidia's RTX 5090 power connectors are melting

#492

Post by xxpor »

fredoliveira wrote: post #335
xxpor wrote: post #299

Earlier quoted context omitted.

Why should we reduce power draw? We live in an age of abundance.

Can you point me to the abundance? Because I sure can point you to the consequences of thinking we live in an age of abundance.

Disposable income has never been higher? One of the world's biggest health problems is everyone eating too much food?

Lack of electricity production is entirely a human choice at this point. There's no need to output carbon to make it happen.

Re: Nvidia's RTX 5090 power connectors are melting

#493

Post by quickthrowman »

DannyBee wrote: post #343
quickthrowman wrote: post #333

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. 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

Yeah, (2) sets of 4”C 4#500MCM #1/0G (copper) is typical for an 800A service. My electricians feel the same way as you do about anything over #500, usually for 400A we parallel #4/0 instead of one set of #500.

Re: Nvidia's RTX 5090 power connectors are melting

#494

Post by caycep »

clhodapp wrote: post #410
Dalewyn wrote: post #389

Earlier quoted context omitted.

Except when the "expected tolerance" is unreasonable. Even if the connectors and wires are to spec, the design leaves next to no margin for play. You need that margin to account for reality : Handling by casual end-users rather than trained professionals, the ambient temperature of the average room or office, dirt and grime that might get lodged and go unnoticed, wonky supply/draw of power, and more. Running 8.3A thr…

There are at least two issues here: 1) The designed safety margin is unacceptably low. It should be set such that any cable that complies with the expected safety tolerance for carrying current is safe to use. 2) The late-model Nvidia cards in particular have no feedback system to discover unbalanced current on 12v wires that make up the connector and no circuitry to keep the current balanced even if they did. That i…

Ok, I have to say this, but the narrator sounds a lot like Jim Henson/Kermit the Frog....(my understanding it is a maryland/mississippi accent combo)

Re: Nvidia's RTX 5090 power connectors are melting

#495

Post by ssl-3 »

snuxoll wrote: post #480
ssl-3 wrote: post #437

Earlier quoted context omitted.

It has long been my understanding that a single regular, bog-standard 15A duplex (ie, dual outlet) receptacle meets the multi-receptacle requirement of a 20-amp branch circuit. If my understanding is correct, then you overkilled it and you could have saved a few dollars, at least one welli-intentioned rant, and still have been compliant with NEC. A literally-single 15A outlet like a Leviton 16251-W would not pass mus…

Well, the rant still applies either way - the 20A outlets are 2x the cost, that's the big reason why the aren't routinely installed. I was thinking when I embarked on the project "oh, I'll just put 20A ones everywhere because why not?" and immediately decided not to when I looked at the prices for the packs of outlets....

Oh, for sure.

I had the luxury (or curse, depending) once of owning a home that needed all of the wiring replaced.

Being the kind of person that I am, I overbuilt things as I felt was appropriate. As part of that, I certainly wanted to install 20 amp outlets (even though I've never held in my hand a 20 amp plug).

The cost of that, vs good spec-grade 15A duplex outlets, was insane.

I know that the only difference is using one T-shaped contact instead of a straight and some different molds for the plastics. The line producing T-shaped contacts already exists, and so do the molds. Every 15A outlet sold today can transfer 20A safely.

It should be pennies difference in cost, and it was instead whole dollars.

Sucks.

(I'm reasonably certain that we are going to be broadly stuck with this low-current, low-voltage business until something very different comes along, and that any of this is unlikely to change in my lifetime.)

Re: Nvidia's RTX 5090 power connectors are melting

#496

Post by ssl-3 »

shawnz wrote: post #460
ssl-3 wrote: post #434

Earlier quoted context omitted.

Here in the States, I've already banished non-Metric "Freedom units" from my workshop. I can do the same with 120v. (And indeed: Back in the mining days, my somewhat diminutive rig was running from a dedicated 240v circuit. It made my already-efficient power supplies a tiny bit more efficient, and it saved a bit on copper. I've already got plans for 240v outlets in the kitchen.)

> I've already got plans for 240v outlets in the kitchen. Likewise, I just need to find a kettle with a NEMA 6-15 plug

I'm OK with installing my own plug into an appliance, like the Brits used to commonly do for approximately everything.

But (and I'm literally splitting hairs here) I'd like to find a 6-15P that has a captive fuse (like US christmas lights have), first:

The 13A maximum that a British appliance expects as a maximum is lower than the 15- or 20- amp circuit breakers that are listed for use in the States.

Unfortunately, it doesn't seem to exist.

Re: Nvidia's RTX 5090 power connectors are melting

#497

Post by ssl-3 »

lsaferite wrote: post #469
shawnz wrote: post #460

Earlier quoted context omitted.

> I've already got plans for 240v outlets in the kitchen. Likewise, I just need to find a kettle with a NEMA 6-15 plug

That was a good chuckle, thanks! The image of that honkin' big plug on a kettle is great!

Maybe you're thinking of NEMA L6-15 or 14-30 or something?

6-15P isn't big or honkin'. It is about the same size as a regular US plug, and differs mostly in that the contacts are just rotated 90 degrees.

If anything, it's a bunch smaller than what much of the rest of the world plugs their own kettles in with, like a British type G or a Schuko.

Re: Nvidia's RTX 5090 power connectors are melting

#498

Post by caycep »

kersplody wrote: post #273

12vhpwr has almost no safety margin. Any minor problem with it rapidly becomes major. 600W is scary, with reports of 800W spikes. 12V2x6 is particularly problematic because any imbalance, such as a bad connection of a single pin, will quickly push things over spec. For example, at 600W, 8.3A are carried on each pin in the connector. Molex Micro-Fit 3.0 connectors are typically rated to 8.5A -- That's almost no margin…

RTX 6000 Ada Gen had EPS12V 8 pin or something?

Re: Nvidia's RTX 5090 power connectors are melting

#499

Post by Dylan16807 »

mschuster91 wrote: post #450
Dylan16807 wrote: post #369

Earlier quoted context omitted.

> The correct solution would be for the GPU to not tie together the incoming individual 12VHPWR pins on a single plane right at the connector input but to use MOSFETs and current/voltage sense to detect stuff like different current availability (at least it used to be the case with older GPUs that there were multiple ways to supply them with power and only, say, one of two connectors on the GPU being used) or overcur…

> It's not hard It still is because in the end you're dealing with dozens of amps on the "high" voltage side and hundreds of amps on the "low" (GPU chip) voltage side. The slightest fuck-up can and will have disastrous consequences. GPUs these days are on the edge of physics when it comes to supplying them with power.

Let me rephrase.

Doing the power conversion is hard.

Realizing that you already have several DC converters sharing the load, and deciding to power specific converters with specific pins, is comparatively easy. And the 3090 did it.

Re: Nvidia's RTX 5090 power connectors are melting

#500

Post by B1FF_PSUVM »

mpreda wrote: post #163
B1FF_PSUVM wrote: post #148

Earlier quoted context omitted.

> Step the GPU voltage up to 48V. Meh. Might as well ask for its own AC cable and be done with it.

But I want fewer cables, not more.

Primary AC cable goes to GPU, and it courteously supplies a short cable to feed the main PSU that only draws half the power ;-)

Tail wags the dog, modern style ...

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