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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

#171

Post by baq »

KeplerBoy wrote: post #119
DannyBee wrote: post #97

Earlier quoted context omitted.

This is because they are trying to parallel like 50amps (it's 12 volt IIRC) over a few conductors to get to 600watts. If it becomes unbalanced due to any number of reasons, none of those individual cables can come close to handling it - they will all generate enough heat to melt lots of things. Conservatively, they'd have to be 8awg each to be able to handle the full load without melting if they ended up taking the f…

If only we had connectors which could actually handle such currents. Maybe something along the lines of an XT90, but no Nvidia somehow wants to save a bit of space or weight on their huge brick of a card. I don't get it.

At these wattages just give it its own mains plug.

Re: Nvidia's RTX 5090 power connectors are melting

#172

Post by Algent »

whywhywhywhy wrote: post #32

People are letting their hatred of Nvidia blind them to what happened here, a customer upgraded from a 4090FE to 5090FE, they were using a 3rd party ASUS 12VHPWR cable and didn't realize the 5090FE actually uses 12V-2x6 not 12VHPWR, while the port is the same the pins are different lengths. End of the day PC power cabling is such a shambles with things that look standard but are not so you should only ever really use…

Another video today from Der8auer showed him reproduce the issue on his model. He showed a 22A load and 150°C point on a single wire. The problem seem to be much worse somehow, clearly no balancing between the wire on the founder edition.

Re: Nvidia's RTX 5090 power connectors are melting

#173

Post by masklinn »

nyrikki wrote: post #168
BizarroLand wrote: post #151

Earlier quoted context omitted.

They could make a new spec for graphics cards and have a 24v/48v rail for them on a new unique connector. I guess the problem is not only designing the cards to run on the higher voltages but also getting AMD and Intel on board because otherwise no manufacturer is going to make the new power supplies.

IIRC the patchwork of laws, standards and regulations across the world for low voltage wiring is what restricted voltage in the 36 V – 52 V range. Some locations treating it as low, some as an intermediate and others treated it as high voltage. It may be marine market specific, but several manufacturers limit to 36v for even high amperage motors because of it. Obviously I=V/R will force this in the future though.

USB PD can go up to 48V so I'd assume that's fine from a regulatory standpoint.

Going from 12V to 48 means you can get 600W through an 8-pin with a 190% safety factor, as opposed to melting your 12VHPWR.

Re: Nvidia's RTX 5090 power connectors are melting

#174

Post by michaelt »

dcrazy wrote: post #120

Is NVIDIA breaching any consumer safety laws by pumping twice the rated current through a 24ish gauge wire? Perhaps by violating their UL certification?

Aren't 12VHPWR cables like https://www.overclockers.co.uk/seasonic-pcie-5.0-12vhpwr-psu... 16AWG ?

Sure, there are problems with the connector. But 600W split over a 12-pin connector is 8.3A per wire, and a 16AWG / 1.5mm² wire should handle that no problem.

Re: Nvidia's RTX 5090 power connectors are melting

#175

Post by Sohcahtoa82 »

dcrazy wrote: post #135
revnode wrote: post #113

Earlier quoted context omitted.

We also have 20 amp wiring, 20 amp breakers, 20 amp sockets, and plugs too. A lot easier than going 240 volt. That will give you 2400 watts max.

Most residential wiring is 15A except for bathrooms.

And kitchens.

Otherwise, running your microwave, toaster, and coffee maker at the same time would likely trip the breaker.

And obviously, the stove/oven is on its own circuit unless it's gas.

Re: Nvidia's RTX 5090 power connectors are melting

#177

Post by Joker_vD »

baq wrote: post #171
KeplerBoy wrote: post #119

Earlier quoted context omitted.

If only we had connectors which could actually handle such currents. Maybe something along the lines of an XT90, but no Nvidia somehow wants to save a bit of space or weight on their huge brick of a card. I don't get it.

At these wattages just give it its own mains plug.

Also put it in a separate case, and give it an OcuLink cable to attach to the main desktop tower. I suspect that's exactly where we're heading, to be fair.

Re: Nvidia's RTX 5090 power connectors are melting

#178

Post by sidewndr46 »

vvv5 wrote: post #16
hgomersall wrote: post #8

Earlier quoted context omitted.

It's 12V, which means the currents are very high (like >40A). It feels like perhaps they need higher voltage power supplies.

I think the problem with this is that chips can only use a relatively low voltage around 1-1.5 volts. So if you supply 48 volts to the card it still has to be stepped down and this means more components and heat dissipation on the card. We are basically arriving at the idea of graphic cards having their own integrated PSUs, but this doesn't fit well with the current physical design of computers.

The cards supply 12 volts today, which is stepped down. There isn't a significant difference between 48 volts and 12 volts other than the amperage

Re: Nvidia's RTX 5090 power connectors are melting

#179

Post by xxs »

DannyBee wrote: post #97
Havoc wrote: post #77

What’s wild is that this is a company clearly capable of designing highly complex things with numerous tradeoffs, challenges and unknowns. And then the fuckin cable is the issue. Repeatedly.

This is because they are trying to parallel like 50amps (it's 12 volt IIRC) over a few conductors to get to 600watts. If it becomes unbalanced due to any number of reasons, none of those individual cables can come close to handling it - they will all generate enough heat to melt lots of things. Conservatively, they'd have to be 8awg each to be able to handle the full load without melting if they ended up taking the f…

The 8awg would need a massive connector, else it will still melt/desolder.

Re: Nvidia's RTX 5090 power connectors are melting

#180

Post by masklinn »

mpreda wrote: post #117
Kirby64 wrote: post #101

Earlier quoted context omitted.

Until the US changes their AC power connectors, we just don’t have a use case for it frankly. When the entire system is going to always top out at 1200W or so (so you have an extra few hundred watts for monitors and such), we’re pretty limited to maximum amperage.

Now I must use lots of rather thick cables in my desktop (because I run GPUs). Imagine that the GPU would instead suck up all the power it needs through the PCIe connector, without all those pesky cables. (right now PCIe can provied 75W at 12V, i.e. 6.25A; that same current would provide 300W at 48V).

The PCIe slot would not be sufficient even if the power architecture moved to 48V: the 12VHPWR are getting 600W pushed through them.
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