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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

#231

Post by RetpolineDrama »

Kirby64 wrote: post #101
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?])

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.

I pulled a fresh 20A (120V) circuit just for my 5090 build.

Re: Nvidia's RTX 5090 power connectors are melting

#232

Post by colejohnson66 »

anankaie wrote: post #188
tass wrote: post #130

Earlier quoted context omitted.

There's also 20 amp circuits which are common. Many houses run circuits that are rated for 20 amps even if they don't have the right outlet for it so this is an inexpensive upgrade for most.

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

Re: Nvidia's RTX 5090 power connectors are melting

#233

Post by burnerthrow008 »

Sohcahtoa82 wrote: post #175
dcrazy wrote: post #135

Earlier quoted context omitted.

Most residential wiring is 15A except for bathrooms.

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.

Don’t forget garages, too.

Re: Nvidia's RTX 5090 power connectors are melting

#234

Post by johnwalkr »

lr1970 wrote: post #191
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…

> If the voltage was higher (i believe 'low volt' classification tops out at 48v) Yep, 48V through sensitive parts of the body could be unpleasant but 24V is almost as safe as 12V. Why didn't they use 24V and 25A to achieve required 600W of power instead of 12V and 50A?

A higher input voltage may eventually be used but a standard PC power supply only has 12V and lower (5V and 3.3V) available, so they'd need to use a new type of power supply or an external power supply, both of which are tough sells.

On the other hand, the voltages used inside a GPU are around 1V, and a higher input voltage introduces lower efficiency in the local conversion.

12V is only really used because historically it was available with relatively high power capacity in order to supply 12V motors in disk drives and fans. If power supplies were designed from the ground-up for power-hungry CPUs and GPUs, you could make an argument for higher voltage, but you could also make an argument for lower voltage. Or for the 12V, either because it's already a good compromise value, or because it's not worth going against the inertia of existing standards. FWIW there is a new standard for power supplies and it is 12V only with no lower or higher voltage outputs.

Re: Nvidia's RTX 5090 power connectors are melting

#236

Post by manwe150 »

anankaie wrote: post #188
tass wrote: post #130

Earlier quoted context omitted.

There's also 20 amp circuits which are common. Many houses run circuits that are rated for 20 amps even if they don't have the right outlet for it so this is an inexpensive upgrade for most.

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 shape of the outlet is different for different current allowances (the spades are wider or rotated). It is supposed to allow an electrician to indicate that the whole circuit is rated to handle the higher expected load, and that there aren’t other outlets on the same circuit which might also try to use the whole current available. Basically a UI problem trying to encourage robust designs for use by non-experts

Re: Nvidia's RTX 5090 power connectors are melting

#237

Post by knowitnone »

lazide wrote: post #76
colechristensen wrote: post #6

If we’re going to keep up these kilowatt scale cards, we’re just going to need higher voltage rails on PSUs. I had a bunch of similar dumb power connector problems when my 4090 was new.

Or just give up and provide a wall power cord.

actually, not a bad idea.

Re: Nvidia's RTX 5090 power connectors are melting

#238

Post by bananadonkey »

Hamuko wrote: post #187
seanw444 wrote: post #137

Earlier quoted context omitted.

Probably reference cards, yeah? I think the common advice is to not buy the reference cards. They rarely cool enough. I made that mistake with the RX 5700 XT, and will never again.

Yeah, they were reference, direct from AMD's own store.

Those had an issue with their heatpipe design which affected cooling performance depending on their orientation. I made sure to buy an AIB model that didn't suffer the same issue, just in case I want to put the card somewhere funky like a server rack.

https://www.tomshardware.com/news/defective-vapor-chamber-ma...

Re: Nvidia's RTX 5090 power connectors are melting

#239

Post by armada651 »

nullifidian wrote: post #230
armada651 wrote: post #197

Earlier quoted context omitted.

Because no PC power supply has a 24V rail and even though there's a fancy new connector you can still use an adapter to get the old-fashioned plugs. After all you don't want to limit your market to people who can afford to buy both your most expensive GPU and a new power supply. In the PC market backwards compatibility is king.

>Because no PC power supply has a 24V rail Servers with NVIDIA H200 GPUs (Supermicro ones for example) have power supplies that have 54 volt rail, since that gpu requires it. I can easily imagine a premium ATX (non-mandatory, optional) variant that has higher voltage rail for people with powerful GPUs. Additional cost shouldn't be an issue considering top level GPUs that would need such rail cost absurd money nowaday…

A server is not a personal computer. We are talking about enthusiast GPUs here who will install these components into their existing setup whereas servers are usually sold as a unit including the power supply.

> Additional cost shouldn't be an issue considering top level GPUs that would need such rail cost absurd money nowadays.

Bold of you to assume that Nvidia would be willing to cut into its margin to provide an optional feature with no marketable benefit other than electrical safety.

Re: Nvidia's RTX 5090 power connectors are melting

#240

Post by Dylan16807 »

cesarb wrote: post #227
opencl wrote: post #196

Earlier quoted context omitted.

Because nobody makes 24V power supplies for computers, they'd have to convince the whole industry to agree on new PSU standards.

> they'd have to convince the whole industry to agree on new PSU standards. We already have a new PSU standard, it's called ATX12VO and drops all lower voltages (5V, 3.3V), keeping only 12V. AFAIK, it's not seen wide adoption.

It's not great. Dropping 5V makes power routing more complicated and needs big conversion blocks outside the PSU.

I would say it makes sense if you want to cut the PSU entirely, for racks of servers fed DC, but in that case it looks like 48V wins.

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