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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

#501

Post by Dylan16807 »

immibis wrote: post #448
Dylan16807 wrote: post #292

Earlier quoted context omitted.

Those are actually at the point of use and unavoidable. I mean extra ones that convert to 5V and then send the power back out elsewhere. All those drives and USB ports still need 5V and the best place to make it is the PSU.

Why is the PSU the best place to make 5 volts? In the distant past it made sense because it allowed some circuitry to be shared between all the different voltages. Now that is not a concern.

The motherboard is cramped, the PSU has a longer life time, and routing power from PSU to motherboard to SATA drive is a mess.

Re: Nvidia's RTX 5090 power connectors are melting

#502

Post by NoPicklez »

numpad0 wrote: post #456
NoPicklez wrote: post #411

Earlier quoted context omitted.

Because often it is the case that third party cables are of higher quality than stock cables, if you purchase from reputable vendors

Gamer judgement on "quality" is often misplaced and skewed towards cosmetic novelty though...

Often, but not always and whilst using third party cables may bring cosmetic appeal, many third parties provide quality cables.

Yes if you buy random cosmetic cables from random Amazon vendors you're running a heavy risk. However there are reputable 3rd party companies that provide both quality cables and cosmetic customization built for your particular power supply.

The same goes for any 3rd party products/accessories.

Re: Nvidia's RTX 5090 power connectors are melting

#503

Post by MBCook »

amluto wrote: post #477
MBCook wrote: post #398

Earlier quoted context omitted.

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 abl…

Math, please. An 800W load is fine on a 120V 15A circuit with plenty of room to spare. The problem is the 12V connection from the PSU to the card.

The national electric code says not to draw more than 80% of the maximum load a circuit can handle continuously. So assuming you plan to game for a reasonable amount of time we’re limited to 12 amps.

That’s 1440 watts. And power supplies for PCs these days seem to be 80-95% efficient for good ones. Let’s say you’ve got a 90%er.

That’s 1300 watts. A top end CPU is 120 watts. Looks like 70-130 watts for a motherboard. Call it 100.

We’re at 1080 watts. Four sticks of DDR5 is another 60 or so. Let’s add 20 for two M.2 drives.

Wait, didn’t we have a 600 watt GPU? Down to 400 left. Good thing dual GPU gaming is dead, we can’t afford a second in our killer gamer system. Let’s add 20 watts for fans so everything doesn’t melt.

So 380 watts left out of 1440. That’s just 25%. But no spinning hard drives or SSDs, no USB PD, no PCI-e cards at all but our one graphics card.

Wait we need a monitor on the same circuit. Looks like that’s 50 watts for a high end LG, 330 now. You did only want one monitor right?

Is it really that hard to imagine hitting that limit soon?

Re: Nvidia's RTX 5090 power connectors are melting

#504

Post by BizarroLand »

masklinn wrote: post #173
nyrikki wrote: post #168

Earlier quoted context omitted.

IIRC the patchwork of laws, standards and regulations across the world for low voltage wiring is what restricted voltage in the 36 V – 52 V range. Some locations treating it as low, some as an intermediate and others treated it as high voltage. It may be marine market specific, but several manufacturers limit to 36v for even high amperage motors because of it. Obviously I=V/R will force this in the future though.

USB PD can go up to 48V so I'd assume that's fine from a regulatory standpoint. Going from 12V to 48 means you can get 600W through an 8-pin with a 190% safety factor, as opposed to melting your 12VHPWR.

Not even to mention the fact that the SXM format Nvidia cards have been running on 48-52v power for a few years already.

Re: Nvidia's RTX 5090 power connectors are melting

#505

Post by pshirshov »

slightwinder wrote: post #92
ulfbert_inc wrote: post #71

Derbauer and Buildzoid on YouTube made nice informative videos on subject, and no it is not "simply a user error". So glad I went with 7900 XTX - should be all set for a couple of years.

> So glad I went with 7900 XTX - should be all set for a couple of years. Really depends on the use case. For gaming, normal office, smaller AI/ML or video-work, yeah, it's fine. But if you want the RTX 5090 for the VRAM, then the 24GB of the 7900 XTX won't be enough.

Radeon Pro W7900

Re: Nvidia's RTX 5090 power connectors are melting

#506

Post by pshirshov »

wing-_-nuts wrote: post #136
slightwinder wrote: post #92

Earlier quoted context omitted.

> So glad I went with 7900 XTX - should be all set for a couple of years. Really depends on the use case. For gaming, normal office, smaller AI/ML or video-work, yeah, it's fine. But if you want the RTX 5090 for the VRAM, then the 24GB of the 7900 XTX won't be enough.

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…

There is tremendous quality difference between 14b and 32b versions.

Re: Nvidia's RTX 5090 power connectors are melting

#507

Post by satvikpendem »

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?

Perhaps that will incentive people to innovate and invent better and more optimized software instead.

Re: Nvidia's RTX 5090 power connectors are melting

#508

Post by lazide »

snuxoll wrote: post #483
lazide wrote: post #452

Earlier quoted context omitted.

At least in the US, a sub panel is an easy grand or two even if it’s right next to the main panel.

A lot is going to depend on labor rates for your local electricians, but that costing more than $500 where I am would be outrageous. I do my own electrical, but even I paid a licensed electrician to come handle installing a new panel since I did not have an outdoor service disconnect and didn't feel like fighting with the utility company over de-energizing and re-energizing my service. Ended up needing a lot more don…

Agreed - I’ve ended up installing 4 (inspected) ones over the years myself, and one I paid an electrician for (they also had to upgrade the main service feed).

IMO, what usually drives up the price is the ancillary stuff - opening up a wall (and re-finishing it) because there isn’t enough physical space, or adding extra main panel capacity/service capacity because the main feed is insufficient, or having to run heavier than expected wiring because the only available space gets really hot (poorly ventilated attic space), or having to run surface conduit due to a specific challenge with framing.

Then add in labor (where I was in a high cost of labor area), and it can get expensive quick.

An actual surface mount subpanel and appropriate wires/breakers is usually only a couple hundred bucks total like you note.

Re: Nvidia's RTX 5090 power connectors are melting

#510

Post by HexPhantom »

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…

At what point do we stop blaming user error and start admitting the design itself is the problem?
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