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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

#351

Post by jmrm »

mpreda wrote: post #100

Step the GPU voltage up to 48V. (anyway you make a new connector that's not compatible with existing PSUs. Why not actually fix a problem at the same time, once and for all! [48V should be enough for anybody, right?])

Not a bad idea IMHO. There are already computers (servers mostly, but also integrated models) who only have 12V power connections and the mainboard does the step-down voltage conversion, and IIRC some companies wanted to do the same to regular desktops.

I would be totally happy if the next gen of computers have 12V outputs to the mainboard and CPU and 48V to the GPU and other power-hungry components. This would make the PCB of those cards a bit bigger, but also would have less power losses and less risk of overheated connectors on the other hand.

Re: Nvidia's RTX 5090 power connectors are melting

#352

Post by colejohnson66 »

malfist wrote: post #338
colejohnson66 wrote: post #232

Earlier quoted context omitted.

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

NEMA 5-20 is only required for commercial. You can use NEMA 5-15 on a 20A circuit for residential in the US.

When I said "should", I didn't mean code required it, but that slapping a 15 amp cover over a 20 amp capable circuit is kindof stupid.

Re: Nvidia's RTX 5090 power connectors are melting

#353

Post by _carbyau_ »

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?

Take a step back, perspectively.

1. People want their desktop computers to be fast. These are not made to be portable battery sippers. Moar powa!!!

2. People have a powerpoint at the wall to plug their appliances into.

Ergo, desktop computers will tend towards 2000w+ devices.

"Insane!" you may cry. But a look at the history of car manufacture suggests that the market will dictate the trend. And in similar fashion, you will be able to buy your overpowered beast of a machine, and idle it to do what you need day to day.

Re: Nvidia's RTX 5090 power connectors are melting

#354

Post by stordoff »

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

AIUI, the connector _on the GPU/PSU_ is slightly different, but the connector on the cable is the same:

> As with any new standard, things are likely to evolve quickly and we’re now seeing the introduction of a new connector on the GPU and the PSU side of things. To be clear, this is not a new cable, it is an updated change to the pins in the socket, which is referred to as 12V-2x6.

Corsair's messaging on Reddit[1] emphasises this:

> Cable is the same. a 12VHPWR cable is a 12V-2x6 cable. it is ONLY the plugs on the graphics card / power supply that have changed.

> The cable is the same. 12VHPWR = 12V-2x6. You will get the exact same cable if you upgrade to a new PSU.

> As mentioned in image one, the cable is the same. Only the plug on the graphics card / PSU changed from 12VHPWR to 12V-2x6.

[1] https://www.reddit.com/r/Corsair/comments/1ha9no1/ive_made_s...

Re: Nvidia's RTX 5090 power connectors are melting

#356

Post by exmadscientist »

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…

This can't be Micro-Fit 3.0, those are only sized to accept up to 18AWG. At least, with hand crimp tooling, and that's dicey enough that I'd be amazed if Molex allowed anything larger any other way. The hand crimper for 18AWG is separate from the other tools in the series, very expensive, and a little bit quirky. Even 18AWG is pushing it with these terminals.

This has to be some other series.

Re: Nvidia's RTX 5090 power connectors are melting

#357

Post by exmadscientist »

ckozlowski wrote: post #291
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…

Great summary. Buildzoid over on YouTube came to a similar conclusion back during the 4xxx series issues[1], and looks like he's released a similar video today[2]. It's worth a watch as he gets well into the electrical side of things. It's been interesting to think that we're probably been dealing with poor connections on the older Molex connectors for years, but because of the ample margins, it was never an issue. N…

> I think the overall mechanism used to make an electrical connection - which hasn't changed much in 30+ years - is probably due for a complete rethink.

There are tons of high-power connectors out there, and they look and work pretty much the same as the current ones (to the untrained eye). They are just more expensive.

Though at 40A+ you tend to see more "banana" type connectors, with a cylindrical piece that has slits cut in it to deform. Those can handle tons of current.

Re: Nvidia's RTX 5090 power connectors are melting

#358

Post by jml7c5 »

ielillo wrote: post #108
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.

The USA has 240 volt plugs. They are only used for high power appliances such as AC or ovens. If you want, you could add a plug for your high powered space heater AKA gaming PC.

Yes, but most people don't want to pay the thousands of dollars to get an electrician to do a rewire.

Re: Nvidia's RTX 5090 power connectors are melting

#359

Post by rollcat »

_carbyau_ wrote: post #353
rollcat wrote: post #242

Earlier quoted context omitted.

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?

Take a step back, perspectively. 1. People want their desktop computers to be fast. These are not made to be portable battery sippers. Moar powa!!! 2. People have a powerpoint at the wall to plug their appliances into. Ergo, desktop computers will tend towards 2000w+ devices. "Insane!" you may cry. But a look at the history of car manufacture suggests that the market will dictate the trend. And in similar fashion, yo…

Well exactly my point. I'm "still" using an M1 Mac mini as my daily driver. 6W idle. In a desktop. It is crazy fast compared to the Intel Macs of the year before, but the writing was already on the wall: this is the new low-end, the entry level.

Still? It runs Baldur's Gate 3. Not smoothly, but it's playable. I don't have an M4 Pro Max Ultra Plus around to compare the apples to apples, but I'd expect both perf and perf per watt to be even better.

If one trillion dollar company can manage this, why not the other?

Re: Nvidia's RTX 5090 power connectors are melting

#360

Post by jml7c5 »

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.

Electricians will almost always install 20 amp sockets where they can, but they avoid running 12 gauge wire because it costs about 50% more.

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