Question RTX 4000 vs Corsair PSU

[JayGau]

I have been reading plenty of posts for a couple of days that are saying that the new RTX GPUs will use PCIe 5.0 power cables and this time around the adapters might not work and even damage your hardware because of the cards high power requirement. Is that true? I bought a Corsair RM1000x not so long ago to make sure I will have enough power for the next few years and now I learn that it may not work with the RTX 4080 that I intend to buy. Even worse, I see that Corsair haven't released any PCIe 5.0 ready PSU yet, so I would need to buy another brand and thus replace all the cables. Also, only a handful of PCIe 5.0 PSU models are available right now. Will they really release cards that are not compatible with 90% of the PSUs on the market?

My guts tell me to just wait and see what the power requirement will be for the new cards. If it's only the high end ones like the 4090 and 4090ti that absolutely require those PSUs there would be no problem (if you have the money to buy one of these you most likely don't mind replacing your PSU) but if everybody who wants a 4070 or a 4080 needs to buy a PCIe 5.0 PSU it's gonna be a nightmare (I don't even want to think about how hard it will be to find one in stock).

 

[logainofhades]

I doubt most vendors are going to change the current standard. Even if they do, they will most likely supply an adapter, like Nvidia did for the founders edition RTX 3000 cards.

 

[JayGau]

I doubt most vendors are going to change the current standard. Even if they do, they will most likely supply an adapter, like Nvidia did for the founders edition RTX 3000 cards.

So AIB manufactures will most likely keep the current standard while the founder edition might use the PCIe 5.0? I read that this time, vendors will not be able to do that if the cards are too power hungry and the problem with the adapter is that you will still have the current standard connected to it and it cannot sustain that much power (having the right connector doesn't increase your cable power capacity). But I should always take what I read online with a grain of salt, especially when we don't even have any official specs yet.

 

[Eximo]

The new 16-pin cable is 12 power pins and 4 data pins. 6 of which are for power. Highest supported mode 600W.

3x PCIe 8-pin is pretty common now. That is a 450W 'rating' over 9 12V pins plus the 75W from the slot. If we go with the common wisdom, 9x60W we get 540W + 75W from the slot.

I see no reason that a triple 8-pin can't support a 450W GPU easily, and there isn't much reason to believe that even more is impossible. All it takes is going up in wire size (which is what will have happened on your RM1000x). Those daisy chained cables should be more than enough to push up to 600W with 3 PCIe 8-pin connectors.

Now any card that asks for dual 16-pin connectors is another matter entirely, but then you yourself would be looking at extreme power supplies to get one running.

 

[JayGau]

@Eximo

Thank you very much for the explanation! That makes sense. I am now pretty confident that I will be good with my RM1000x.

 

[sizzling]

It would be seriously limiting to sales to force everyone to upgrade their psu and possibly motherboard at the same time.

 

[Eximo]

Certainly for any single consumer grade GPU likely to be released in the next short while. ATX 3.0/3.1 etc may be more necessary as power requirements change in either efficiency or capability, not necessarily wattage increases.

PCIe 5.0 power connectors have little to do with motherboards (though I do hope they consider adopting a new EPS connector standard at some point)

I am still looking forward to true 12VO adoption.

 

[NoFaultius]

I'm sure the power adapters that are packaged by the manufacturer with the new cards will be appropriate and safe to use with your existing power supply. That is a good quality gold rated power supply you have.

 

[Eximo]

12-pin adapter that comes with the card, fine, but using a power supply with the appropriate number of connectors and wattage is necessary.
Using additional adapters to make a power supply work with an adapter is unwise.
The PSU in your thread was marginal at best for a 30 series card, not necessarily due to a lack of connectors, but just general quality. Though the discussion didn't really touch on that. 30 series cards are well known for their transient spikes that can trip a shutdown with even what seems like properly sized wattage ratings.

And the general advice is absolutely true. If your power supply doesn't have the proper connectors for running a particular graphics card, you should not use aftermarket adapters to make it work. There are terrible 4-pin to 6-pin adapters which is wrong on the face of it, 1 12V wire does not become 2 12 V wires magically. And the same is true of single six-pin to 8-pin adapters, or the worst SATA to six-pin. That is what the maxim is intended for, trying to run a GPU with an underrated PSU without adequate power or wiring. Unscrupulous people do it all the time when converting office PCs to light gaming machines.

Taking 3 8-pins and using them to make a 16-pin adapters is fine. As mentioned going from 9 12V pins to 6 is not a big deal. But this comes with its own caveats. For example a Corsair RM750x would be marginal with something like that. It only has two daisy chained 6+2 connectors for a total of 4 8-pin PCIe connectors. But to expect it to deliver 600W for just a GPU, plus transients, plus the rest of the system, no it would probably trip. But there will be PCIe 5.0 adapters that only require two 8-pins, and that would be fine because the card would be expected to be something like 300W only.