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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

#261

Post by truncate »

rollcat wrote: post #242
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…

Can we talk about how absolutely terrifying is that 600W figure? We're not transcoding or generating slop as the primary use case, we're playing computer games . What was wrong with the previous-generation graphics that we still need to push for more raw performance, rather than reducing power draw?

Is the primary use case for *090 series gaming anymore? 5070 which is probably what most popular gaming card is 250W. If I recall correctly it can push 4k @ 60fps for most games.

But yes, I do agree that TDPs for GPUs are getting ridiculous.

Re: Nvidia's RTX 5090 power connectors are melting

#262

Post by 6SixTy »

michaelt wrote: post #144
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.

The USB-C connectors on laptops and phones can deliver 240 watts [1] in a 8.4x2.7mm connector. 12VHPWR is 8.4x20.8mm so it's got 7.7x the cross-sectional area but transmits only 2.5x the power. And 12VHPWR also has the substantial advantage that GPUs have fans and airflow aplenty. So I can see why someone looking at the product might have thought the connector could reasonably be shrunk. Of course, the trick USB-C us…

Nobody thought that they could push 50A at 12V through half the connector. It's management wanting to push industrial design as opposed to safety. They made a new connector borrowing from an already existing design, pushed up the on paper amperage by 3A, never changed the contact resistance, and made the parent connector push current near it's limit (10.5A max vs 8.3A). And oh, the insertion force is so, so much higher than ever before. Previous PCIe connectors push about 4A through a connector designed for about 13A.

Worth also mentioning that the same time the 12VHPWR connector was being market tested was during Ampere, the same generation where Nvidia doubled down on the industrial design of their 1st party cards.

Also there's zero devices out there that actually deliver or take 240W over USB-C. Texas Instruments literally only released the datasheets for a pivotal supporting IC within the last 6 months.

Re: Nvidia's RTX 5090 power connectors are melting

#263

Post by wing-_-nuts »

diggan wrote: post #211
wing-_-nuts wrote: post #136

Earlier quoted context omitted.

Honestly, the smart play in that case is to buy 2 3090's and connect them with nvlink. Or...and hear me out, at this point you could probably just invest your workstation build budget and use the dividends to pay for runpod instances when you actually want to spin up and do things. I'm sure there are some use cases for 32gb of vram but most of the cutting edge models that people are using day to day on local hardware…

> most of the cutting edge models that people are using day to day on local hardware fit in 12 or even 8gb of vram. I'm not sure what your idea of "day to day" use cases are, but models that fit in 12GB of VRAM tend to be good for like autocomplete and not much more. I can't even get those models to chose the right tool at the right time, even less be moderately useful. Qwen2.5-32B seems to be the lower boundary of a…

Yes I was gonna mention that Qwen model from the deepseek folks as maybe an exception

Re: Nvidia's RTX 5090 power connectors are melting

#264

Post by ObscureScience »

armada651 wrote: post #239
nullifidian wrote: post #230

Earlier quoted context omitted.

>Because no PC power supply has a 24V rail Servers with NVIDIA H200 GPUs (Supermicro ones for example) have power supplies that have 54 volt rail, since that gpu requires it. I can easily imagine a premium ATX (non-mandatory, optional) variant that has higher voltage rail for people with powerful GPUs. Additional cost shouldn't be an issue considering top level GPUs that would need such rail cost absurd money nowaday…

A server is not a personal computer. We are talking about enthusiast GPUs here who will install these components into their existing setup whereas servers are usually sold as a unit including the power supply. > Additional cost shouldn't be an issue considering top level GPUs that would need such rail cost absurd money nowadays. Bold of you to assume that Nvidia would be willing to cut into its margin to provide an o…

Electrical safety -> not destroying your GPU does seem like something sellable.

It could probably be spinned into some performance pitch if you really want to.

Re: Nvidia's RTX 5090 power connectors are melting

#265

Post by ninth_ant »

rollcat wrote: post #242
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…

Can we talk about how absolutely terrifying is that 600W figure? We're not transcoding or generating slop as the primary use case, we're playing computer games . What was wrong with the previous-generation graphics that we still need to push for more raw performance, rather than reducing power draw?

What was “wrong” is that enough people are willing to pay exorbitant prices for the highest-end gear that Nvidia can do most anything they want as long as their products have the best numbers.

Other companies do make products with lower power draw — Apple in particular has some good stuff in this space for people who need it for AI and not gaming. And even in the gaming space, you have many options for good products — but people who apparently have money to burn want the best at any cost.

Re: Nvidia's RTX 5090 power connectors are melting

#266

Post by superjan »

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…

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.

Re: Nvidia's RTX 5090 power connectors are melting

#267

Post by FirmwareBurner »

ziddoap wrote: post #256
FirmwareBurner wrote: post #216

Earlier quoted context omitted.

An old legacy car is definitely not more complicated than designing and manufacturing a cutting edge silicon made for high performance compute. The price difference is just the free market supply and demand at work. People and businesses pay more for the latest Nvidia GPUs than for an old car because for their use case it's worth it, they can't get a better GPU from anywhere else because they're complex to design and…

> An old legacy car is definitely not more complicated than designing and manufacturing a cutting edge silicon made for high performance compute. A car is more complicated than a connector, at least. Anyways, the rest of your comment is again taking a humorous one-liner way too seriously. Thanks for the econ lesson though, I guess. I liked the part where you explained to me the basics of supply and demand like I am i…

>A car is more complicated than a connector, at least.

The connectors on a new car cost more than the connectors on a new GPU part for part.

>I liked the part where you explained to me the basics of supply and demand like I am in 5th grade.

You'd be surprised about the state of HN understanding of how basic things in the world work.

Re: Nvidia's RTX 5090 power connectors are melting

#268

Post by forza_user »

opencl wrote: post #196
lr1970 wrote: post #191

Earlier quoted context omitted.

> If the voltage was higher (i believe 'low volt' classification tops out at 48v) Yep, 48V through sensitive parts of the body could be unpleasant but 24V is almost as safe as 12V. Why didn't they use 24V and 25A to achieve required 600W of power instead of 12V and 50A?

Because nobody makes 24V power supplies for computers, they'd have to convince the whole industry to agree on new PSU standards.

24VDC is the most common supply for industrial electronics like PLCs, sensors etc. It is used in almost every type of industrial automation systems. 48VDC is also not uncommon for bigger power supplies, servos, etc.

https://www.siemens.com/global/en/products/automation/power-...

Re: Nvidia's RTX 5090 power connectors are melting

#270

Post by immibis »

cesarb wrote: post #214
baq wrote: post #171

Earlier quoted context omitted.

At these wattages just give it its own mains plug.

> At these wattages just give it its own mains plug. You might think you're joking, but there are gamer cases with space for two PSUs, and motherboards which can control a secondary PSU (turning both PSUs on and off together). When using a computer built like that, you have two main plugs, and the second PSU (thus the second mains plug) is usually dedicated to the graphics card(s).

I've done this, without a case, not because I actually used huge amounts of power, but because neither PSU had the right combination of connectors.

The second one was turned on with a paperclip, obviously.

Turns out graphics cards and hard drives are completely fine with receiving power but no data link. They just sit there (sometimes with fans at max speed by default!) until the rest of the PC comes online.

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