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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

#311

Post by Denvercoder9 »

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…

> A 48V system would have only ~13% the resistive losses over the cables (more importantly, at the connections!)

It's one-sixteenth (6.25%) actually. You correctly note that resistive losses scale with the square of the current (and current goes with reciprocal voltage), so at 4 times the voltage, you have 1/4th the current and (1/4)^2 = 1/16th the resistive losses.

Re: Nvidia's RTX 5090 power connectors are melting

#312

Post by DebtDeflation »

Miraste wrote: post #300
michaelt wrote: post #144

Earlier quoted context omitted.

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…

The spec may say it, but I've never encountered a USB-C cable that claims to support 240 watts. I suspect if machines that tried to draw 240W over USB-C were widespread, we would see a lot of melted cables and fires. There are enough of them already with lower power draw charging.

Search Amazon for "240W USB" and you get multiple pages of results for cables.

A few years ago there was a recall of OnePlus cables that were melting and catching fire, I had 2 of them and both melted.

But yes 240W/48V/5A is insane for a spec that was originally designed for 0.5W/5V/100mA. I suspect this is the limit for USB charging as anything over 48V is considered a shock hazard by UL and 5A is already at the very top of the 3-5A limit of 20AWG for fire safety.

Re: Nvidia's RTX 5090 power connectors are melting

#313

Post by Workaccount2 »

rasz wrote: post #201
Workaccount2 wrote: post #104

Earlier quoted context omitted.

I work in power electronics and there are ample connectors that can handle any type of power requirement. What is happening in the computer space is that everyone is clinging to an old style of doing things, likely because it is free and open, and suggestions to move to new connectors get saddled with proprietary licensing fees. D-sub power connectors have been around forever (they even look like the '90s still) and…

You are proposing connector with exposed live 12V pins.

The GPU and PSU would have female ports and the cable would be male.

12V isn't dangerous to humans, but it could spark quite a bit if it hit the computer chassis.

Re: Nvidia's RTX 5090 power connectors are melting

#314

Post by erinaceousjones »

whywhywhywhy wrote: post #159
stordoff wrote: post #60

Earlier quoted context omitted.

At least according to Corsair, there are no changes to the cable, only the PSU/GPU-side connectors: > Cable: 12V-2x6 = 12VHPWR No difference! > So what does this mean if you’ve already got hardware for 12VHPWR? Fortunately, existing 12VHPWR cables and adapters will work with the new 12V-2x6 connector as the new changes are only related to the GPU and some PSUs (Our new RMx PSUs for example). The cables you've got alr…

Connectors are where the issue is and there is a difference even if they fit in the same plugs and power can still go through them. From your link > Compared to the original 12VHPWR connector, the new 12V-2x6 connector has shorter sensing pins (1.5mm) while the conductor terminals are 0.25mm longer

That's inconsistent messaging from Corsair, then. Parent comment quotes the times they're like "ehh, they're same thing, don't worry about it" and then they go on to say "well TECHNICALLY there's a teeensy difference in conductor sizes"???

Either they are confident that the 0.25mm terminal difference is within tolerance enough that they consider 12VHPWR to be functionally equivalent to 12V-2x6, or they're getting themselves confused let alone the target audience of their article.

Re: Nvidia's RTX 5090 power connectors are melting

#315

Post by crote »

6SixTy wrote: post #262
michaelt wrote: post #144

Earlier quoted context omitted.

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 high…

> 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.

The 16-inch Framework laptop can take 240W power. For chargers, the Delta Electronics ADP-240KB is an option. Some Framework users have already tried the combination.

Re: Nvidia's RTX 5090 power connectors are melting

#316

Post by Denvercoder9 »

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.

It's not an engineering problem, it's a political problem. If you present this problem to any power engineer at Nvidia, they'd probably say something akin to "yeah, delivering 600W at 12V over a 12-prong connector is insane, up the voltage". The issue is that 12V has been the standard voltage for ages, and if you want to sell a product that requires a higher voltage, you first need to get the industry to produce PSUs that deliver a higher voltage.

Re: Nvidia's RTX 5090 power connectors are melting

#317

Post by UberMouse »

jgalt212 wrote: post #288
jorgemf wrote: post #251

Earlier quoted context omitted.

This genereation seems that is getting performance using more power and more cores. Not really an architectural change but only packing more things in the chip that require more power.

Too true. I've been looking replace my 1080. This was a beast in 2016, but the only way I can get a more performant card these days is to double the power draw. That's not really progress.

Then get a modern GPU and limit the power to what your 1080 draws. It will still be significantly faster. GPU power is out of control these days, if you knock 10% off the power budget you generally only lose a few percentage of performance.

Cutting the 5090 down from 575w to 400w is a 10% perf decrease.

Re: Nvidia's RTX 5090 power connectors are melting

#318

Post by CobaltFire »

CommieBobDole wrote: post #90
buffet_overflow wrote: post #81

Earlier quoted context omitted.

Reminds me a bit of BMWs and their infamous and persistent coolant pump woes. The running joke in those circles is "replacing the entire cooling system" counts as "basic, regular maintenance". BMW makes a fantastic engine, then makes the water pump impeller out of plastic. For what feels like decades.

My E39 (which is a beacon of reliability for the brand) had a radiator neck made of a kind of plastic that becomes brittle with prolonged exposure to heat. It's a good thing there's no heat associated with the radiator. "Replace the entire radiator" was a ~70k mile maintenance task.

Yup, mine blew apart in traffic on H1 (Oahu) at 35MPH when the car (530i) was ~3 years old. I think it had maybe 35k miles on it.

Dealer offered to allow me to pay extra for an all aluminum since that’s what they recommended but the factory wouldn’t cover.

Re: Nvidia's RTX 5090 power connectors are melting

#319

Post by 0x457 »

immibis wrote: post #270
cesarb wrote: post #214

Earlier quoted context omitted.

> 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.

You can also hookup a little thingy that takes sata power on one side and 24 pin on the other. As soon as there is power on sata side, relay switches and second PSU turns on.

Re: Nvidia's RTX 5090 power connectors are melting

#320

Post by CobaltFire »

CommieBobDole wrote: post #245
karolist wrote: post #200

Earlier quoted context omitted.

E39 beacon of reliability, is this sarcasm? I really can't tell

It's not, actually - the E39s are incredibly reliable compared to more recent models. I drove mine for 20 years. That said, it's the difference between "fairly unreliable" and "spectacularly unreliable".

I miss mine enough I’ve been debating on buying another.

A 530i Sport with a manual (!!!) popped up near me for a song but I just can’t justify it.

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