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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

#511

Post by Schiendelman »

deelowe wrote: post #479
Schiendelman wrote: post #455

Earlier quoted context omitted.

I'm not familiar with this! I've tried to investigate but I just get variable refresh rate. Tell me more?

Voltage regulators. Voltage regulation technology is extremely advanced as even very small efficiency gains can save billions for hyperscalers. Unfortunately, I don't know of any specific products to share as power isn't my domain. I'm only familiar with the space because we sometimes have to pull telemetry directly from the VRs when doing system level RCAs. Some of our BMCs can do this directly via I2C.

No that's okay, thank you for the pointer in the right direction!

It doesn't look to me like anything out there can take voltage from 48v to 2-3v; at least not obviously.

Re: Nvidia's RTX 5090 power connectors are melting

#512

Post by tlb »

I've designed PCBs using connectors with multiple parallel wires to carry high currents. It's hard to do, and very easy to mess up during later PCB changes. You have to match trace resistances from each pin to the destination. The resistance in the traces is probably higher than the resistance in the wires, so the wires don't help balance the current much.

It's easy to mess up during minor PCB changes because the netlist doesn't capture the important bit. An autorouter would happily connect the pins of the connector together and cause uneven current sharing.

Re: Nvidia's RTX 5090 power connectors are melting

#513

Post by Kirby64 »

ryao wrote: post #295
Sohcahtoa82 wrote: post #175

Earlier quoted context omitted.

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.

My kitchen has at least 2 120VAC circuits, which seems to avoid this.

NEC code requires 2 separate 20 amp circuits in a kitchen. Usually they split the circuits across a countertop or window. It's been code since ... as far as I can tell, pretty much forever. Unless you're living in a house that is either non-compliant or built before NEC was required, then it should have this kitchen arrangement.

Re: Nvidia's RTX 5090 power connectors are melting

#514

Post by Kirby64 »

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.

We can agree they're less common than the UK, but saying they have "no use case" is a gross exaggeration. Pretty much everyone I know owns a kettle, given how cheap they are (~$15-20 for an OK one). Great for hot chocolate, coffee, tea, boiling water for a pot of water (to speed it up vs heating up your entire house), and numerous other reasons.

Re: Nvidia's RTX 5090 power connectors are melting

#515

Post by dragonwriter »

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.

There are plenty of use cases in America, and electric kettles are not uncommon here, even if they are less common than in the UK.

Re: Nvidia's RTX 5090 power connectors are melting

#516

Post by Kirby64 »

ryao wrote: post #297
Kirby64 wrote: post #241

Earlier quoted context omitted.

We do, but they’re limited to much lower wattage due to the outlet limits. A typical US kettle is 1100-1400W, and takes maybe 1-2 minutes to boil. Kettles in the UK are typically 2.5-3kW.

Amazon lists 1500W models: https://www.amazon.com/electric-kettles/b

What's your point? There's likely a few 1800W kettles that exist too. They are not common, and you definitely will never see anything above 1800W (outside of maybe some specialized commercial product designed for an 20A outlet) in the US. A 'normal' average kettle is going to be ~1200W here. Kettles start at 2kW and go up from there in the UK.

Re: Nvidia's RTX 5090 power connectors are melting

#517

Post by bcrl »

Dalewyn wrote: post #383
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…

What is the reason the spec keeps specifying next to no headroom? Clearly that was the fundamental problem with 12VHPWR and it's being repeated with 12V2X6. Any engineer worth his salt knows that you should leave plenty of headroom in your designs, you are not supposed to stress your components to (almost) their maximum specifications under nominal use.

I found it hilarious when a friend went to use a Tesla supercharger on his F150 Lightning. As the cable is only long enough to reach the charge port on the corner of a Telsa, he had to block 2 parking spaces and almost 3 chargers to use it. Oops... I hope all the money "saved" on copper was worth it.

Re: Nvidia's RTX 5090 power connectors are melting

#518

Post by parineum »

xquce wrote: post #429
parineum wrote: post #415

Earlier quoted context omitted.

> 5080 is really more of a 70 series Oft repeated, never explained. The numbers don't really mean anything and never have. 5080 is faster than the 5070 is faster than the 5060. That's what the number means. The performance gap between tiers isn't and has never been constant.

Often explained, always ignored https://youtu.be/J72Gfh5mfTk Everyone who cares to know about generational improvements have indeed compared performance between tiers. No they have never been conctant but the "best" generations clearly had better segmented tiers in their generation compared to prior. Adding "fake" frames to say the 5070 has the performance of the 4090 like Jensen, tells you even Nvidia do this compar…

> Adding "fake" frames to say the 5070 has the performance of the 4090 like Jensen, tells you even Nvidia do this comparison.

You're missing the point. The only thing that makes a 5080 a 5080 is that's what NVIDIA named it. of course comparisons are going to be made but it's meaningless to expect the numbers to correlate to some specific performance gain over the lower tier or previous generation.

The lineup is different every year. The metric that matters is performance per dollar, not the name of the product.

The 80 tier isn't great value this generation. That doesn't make it really a 5070.

Re: Nvidia's RTX 5090 power connectors are melting

#519

Post by choilive »

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…

I would bet a lot of money more than 1 engineer at nvda flagged this as a potential issue. If you were going to run this close to the safety margin, I would at minimum add current sensing on each pin.

Re: Nvidia's RTX 5090 power connectors are melting

#520

Post by fennecfoxy »

Idk why we haven't migrated to better power standards for PC/computers.

I loathe those molex connectors, especially the 24-pin mobo one; it's just ridiculously massive/overcomplicated.

Like, instead of the very rectangular 24-pin with a flat but wiiiiide cable, why don't we have a circular connector with a circular cable that is a lot more manageable for mini-itx builds.

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