Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Nvidia's RTX 5090 power connectors are melting

theverge.com

Post reply on HN
Print view View original

391–400 of 526 posts

Re: Nvidia's RTX 5090 power connectors are melting

#391

Post by snuxoll »

flyingpenguin wrote: post #149
ielillo wrote: post #108

Earlier quoted context omitted.

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.

The problem there would be your breaker. I am not an electrition but I can tell you that when I tried adding a heated MAU to my house, I had to switch to a 120v washer/dryer because my electric panel did not have space for another 208v line. (Note, my building is actually 3 phase 208 volt not 240volt so I don't have 240 volt plugs but 208volt plugs)

Not a criticism, but a question. Did you consider adding a subpanel? If you're running a new circuit I assume there was already some drywall patching to be done, seems like it would have been more cost effective and removed future headaches to just give yourself more breaker space.

Re: Nvidia's RTX 5090 power connectors are melting

#392

Post by hipsterstal1n »

rangestransform wrote: post #346
nvarsj wrote: post #302

I would love to get some insight from Nvidia engineers on what happened here. The 3 series and before were overbuilt in their power delivery system. How did we get from that to the 1 shunt resistor, incredibly dangerous fire-hazard design of the 5 series? [1] Even after the obvious problems with 4 series, Nvidia actually doubled down and made it _worse_! The level of incompetence here is actually astounding to me. Nv…

Not sure if this is related but a friend there said a lot of people retired

My boss has a few neighbors who are Nvidia and former Nvidia employees and they're all driving their shiny, fancy sports cars and such and living the high life thanks to the stock they got. It doesn't surprise me they're having churn and / or retiring cutting in to their workforce. Probably not enough to be substantial, but enough to count for something.

Re: Nvidia's RTX 5090 power connectors are melting

#394

Post by aaronmdjones »

ryao wrote: post #287
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).

Server systems already work like this for redundancy.

No they don't. Server-grade redundant PSUs usually use a CRPS form factor, where individual PSU modules slot into a common multi-module PSU housing known as a PDB (power distribution board). Each module typically outputs only 12V and the PDB manages the down-conversion to 5V, 5VSB, and 3.3V. From there, there is only one set of power cables between the PDB and the system's components including the motherboard and any PCIe add-in cards. Additionally, there is a PMBus cable between the PDB and the motherboard so that the operating system and the motherboard's remote management interface (e.g. IPMI) can monitor the status of each individual module (AC power present, measured power input, measured power output, measured voltage input, measured frequency input, fan speeds, temperature, which module is currently powering the system, etc).

PSUs can be removed from the PDB and replaced and reconnected to a source of power without having to shut down the machine or even remove the case lid. You don't even need to slide the machine out of the rack if you can get to the rear.

Example:

https://www.fspgb.co.uk/_files/ugd/ea9ce5_d90a79af31f84cd59d...

Re: Nvidia's RTX 5090 power connectors are melting

#395

Post by snuxoll »

tass wrote: post #341
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

> The electrician should be installing 20 amp sockets if the cabling can support it, but many don't. I think this is mainly because the 20 amp outlets are kind of ugly, and the fact that barely anything actually uses a 20 amp plug. In my house, almost every circuit has a 20 amp breaker and 12 ga (yellow) romex, but only a couple of outlets are 5-20.

20a outlets are also expensive compared to 15A ones. When redoing the electrical in the house I inherited I put a dedicated circuit in the living room for the TV/game consoles/etc since my daughter's gaming rig would be going in the living room as well; since I hadn't decided to put the recessed panel for the TV wiring in at the time it was the only outlet on the circuit and code dictates that a 20A circuit with a single outlet must use a 20A receptacle.

I can buy a 10-pack of nice 15A Leviton Decora Edge outlets (that use lever lock connectors instead of screw terminals) for $26 ($2.60 each), but basic 20A tamper resistant outlets (which newer editions of the NEC require anywhere a small child can access them) are $6+ a pop.

When nothing outside of my electrical room (where the servers live) has need of a 20A receptacle it's kind of pointless to spend the extra money on them, but the extra couple bucks on 12 gauge copper is always wise.

Re: Nvidia's RTX 5090 power connectors are melting

#396

Post by kristianp »

On a side note, there are no 5090's on amazon.com, except as part of a system. I suppose this is because any that become available are purchased and amazon doesn't display out of stock items in their search results? There are 5080's.

https://www.amazon.com/s?k=nvidia+rtx+5090+32gb+ddr7&i=elect...

Re: Nvidia's RTX 5090 power connectors are melting

#397

Post by snuxoll »

colejohnson66 wrote: post #352
malfist wrote: post #338

Earlier quoted context omitted.

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.

Not really. 15A receptacles are required by code to be able to handle 20A of current at their terminals, so the larger wire and breaker allows for more loads to be run instead of one big load to draw it all (and if you need that, then a 20A circuit with a single receptacle does actually require it to be a 20A receptacle).

Re: Nvidia's RTX 5090 power connectors are melting

#398

Post by MBCook »

shawnz wrote: post #364
MBCook wrote: post #350

Earlier quoted context omitted.

Maybe having cards drawing >500/600 watts is just a bad idea. Add in a CPU and such and we’re quickly approaching the maximum amount of power that can be drawn from a standard 12 amp circuit continuously.

What's the proposal here, just convince everyone to stop demanding more powerful hardware?

Stop and try again?

Either you’re not going to get a choice, or you’ll need a 240v three phase outlet installed and possibly an expanded electrical panel.

Nvidia has been all about “as fast as possible, no compromise” for a very long time now. So was Intel, until the Pentium 4 forced a big reset.

At a certain point this stuff is just totally untenable. Throw more amps at it stops being workable.

Apple seems to be able to get a decent fraction of the performance using drastically less power. I have the impression Intel is doing the same, though I’m less sure on that one.

Given how parallel graphics problems are, maybe it’s time to give up on 100 cores that go uber fast as behave like a space heater and move to 250 cores that go quite fast but use 1/4 of the power each.

Re: Nvidia's RTX 5090 power connectors are melting

#399

Post by aaronmdjones »

0x457 wrote: post #319
immibis wrote: post #270

Earlier quoted context omitted.

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.

This may not be fast enough for some add-in cards. It would be better to connect the PS_ON (green) cable from both ATX24 connectors together, so that the motherboard turns on both PSUs simultaneously.

This would still have the disadvantage that the PWROK (grey) cable from the second PSU would not be monitored by the motherboard, leaving the machine prone to partial reset quirks during brown-outs. Normally a motherboard will shut down when PWROK is deasserted, and refuse to come out of reset until it returns.

Re: Nvidia's RTX 5090 power connectors are melting

#400

Post by opello »

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…

This [1] is also a good deep dive into the space covering the spec, limits, and materials details. For example:

> The specification for the connector and its terminals to support 450 to 600W is very precise. You are only within spec if you use glass fiber filled thermoplastic rated for 70°C temperatures and meets UL94V-0 flammability requirements. The terminals used can only be brass, never phosphor bronze, and the wire gauge must be 16g (except for the side band wires, of course).

[1] http://jongerow.com/12VHPWR/

Post reply on HN