It’s something of a contentious issue. And it really has to do with the differences between ratings and how much current these cables can actually handle which is frequently more than double their rated limits. Running over their rated limits is reducing your safety margin though.
Here’s what Corsair itself has to say on the matter of powering the 4090 using the adapters with it’s PSUs:
Excerpt from that link: “so for the adapter supplied with the new RTX 4090 you’ll need three dedicated PCIe 8-pin power connectors (from separate cables coming off of your PSU)”
Frankly, it will work with the daisy chain, but you shouldn’t. My take on it is that if you’re able to cable it properly, do that. If for some reason that’s impossible, then go ahead and use the daisy chain. You’re not likely to actually run into problems, but at least be a little more careful that your connections are good. These things are overspec’ed for safety primarily so they’ve still got enough capacity when connections are poor and only some of the wires are having to take the entire load. Monitor your power cables to make sure they’re not heating up when the GPU is drawing full power (playing a game). If it’s sustaining without getting hot, you’re good.
… The adapters may have changed since the 4090 does not require the performance originally planned. There are sense lines in the plug, so that the first cards with only two or with the OC (like mine) 3 connections do not even go into operation. If two lines are also working now, something has changed there.
From a certain cable thickness, 2x8 are sufficient for the Corsair. The Rm850x is at 12 volt single rail. The cable that will be available from Corsair in the future will only have two connectors.
As far as I can remember, the white Corsair Cable are a little bit thicker as other.
With all due respect, you are incorrect. You do not run the cables above spec using both plugs. He has a PSU with 16 awg wires for the connectors. Each 8 pin connector has 3 power loops. 16 awg can handle 10 A all day long, no issues. 3 loops means 30A*12V = 360W on that cable alone. Please don’t spread misinformation like this. And you do not run 300W through the first plug in the daisy, it’s just a junction only 150W will flow through the each plugs pins and into the card. Corsair would not have made this option available if it would risk melting the cables or burning your house down, c’mon now…
Edit: The only way I can see this as a potential problem is if one of the plugs fails while the sense pin in the 12vhpwr for some reason still tells the card it is OK to pull the full load, but then you have a 2 point error which imo is highly unlikely. That’s why it would be considered not ideal.
I know with my 3 x 8 pin MSI Trio 4090 it came with a warning leaflet saying not to daisy chain PCIE cables. It said to use 3 separate PCIE cables, here’s a pic of it from YouTube :
I’m quoting from Corsair’s own website. If it’s misinformation, then it’s coming from Corsair.
There was also a YouTube video where a representative from Corsair was explaining why their 12vhpwr cable is able to be rated for 600 watts with only two type 4 cables going into the PSU when using the adapter requires four individual type 4 cables to achieve the same rating. There are not only different wire gauges involved in Corsair’s 12vhwpr cable but it also has to do with spreading the load across different pins at the PSU connections. I don’t have a link to that handy though. I think it might have been a segment within one of the Gamers Nexus videos.
I do think you’re right in that this these things will actually work as you’ve described. My impression is that Corsair is going for an overabundance of caution concerning the 12vhpwr and having everything way over-specified. But I think your conflict here is with Corsair, not me. I’m just passing along Corsair’s official recommendations. Unless you can find a link to something from Corsair that contradicts what I’ve posted?
The reason for Corsair is doing that is to be able to follow the ATX standard of 50W per wire. This will also cover every possible configuration, both high end stuff and cheap garbage that might blow up if pulling too much. There are PSUs that can’t handle the power of a daisy over just one cable if someone was to buy an adapter as an example. Hence the recommendation of always use 4 is the easiest way to not cause confusion and lawsuits. I agree, it’s the allround safest approach, but I was giving my comments in regards of the hardware Armorgeddon has, not on a general basis. In his case there is no need for more than 3 cables if he ain’t coverclocking (He won’t be able to without the 4th even if he tried as the power limiter will be locked at 100%/450W). You are making it seem like he is running a potential dangerous setup, which is not correct, neither is your comment that he is overloading his cables by using a daisy. For other systems your comments might be perfectly valid though.
If he had 4 cables, of course, plug them in to spread the load further, but there is by no means reasons for him to upgrade his PSU to get a safer system with a 4th cable. That’s what I wanted to point out. I don’t disagree on the general recommendation.
There is no magic over this. It comes down to what I’ve been trying to explain. A 8 pin connector with 16 awg wires will be able to pass over 300W, given that the PSU is up for the task. Hence the need for only 2 in their “special” cable. The specs for the plug (Molex) and the ATX standard of 150W are two different things. The ATX standard is a minimum quality that manufacturers will have to fulfill.
The hardware he has is Corsair. The recommendation is from Corsair for Corsair’s hardware.
According to Corsair’s recommendations for Corsair’s products, he is running a potentially dangerous setup. That is literally what not following the PSU manufacturer’s recommendations means.
In Raymondo’s opinion, that configuration is safe enough. In Corsair’s opinion, it is not.
I’m not going to discuss this further with you, because you do not seem to understand (or just can’t admit that someone else has a correct answer). I already explained to you why Corsair is doing that. As a side note, I do know what I’m talking about as I carry a Bachelor within electronics. So I leave it up to OP to decide for himself what he wants to do, but from an electrical pov his system is safe, period.
What I have explained is electrical facts based upon actual specifications for the equipment in use. What recommendation Corsair is communicating is a general recommendation based on the ATX standard. He has a high quality PSU which exceeds ATX. Corsair would not (!) supply a cable that is not at least dimensioned to fulfill ATX/150W standard on both plugs on the daisy.
@Sargon this is not the first time you went against supporting hints of other participants of a thread. It really seem you want to dominate and show you are always right and know better than everybody here.
There are lot´s of threads here where you are involved. You never stop trolling.
I find it disgusting, just awful behavior.
I am lucky not to be a moderator here.
You will be on my personal block list
Edit: typo
Okay I am going to stop you here. Both you and @Sargon are correct.
However regardless of a wire’s specification a manufacturer’s specification recommendation supercedes its. In the case of Corsair following the ATX standard or if they choose to be even more cautious. This is done to ensure liability does not fall on the manufacturer in the possible chance of failure.
If you ignore the manufacturer’s safety recommendations should for any reason a failure occurs. The manufacturer should not be held liable
What your saying about the wire’s true specification is true. However in the application from say Corsair. Corsair specification trumps it for purposes of warranty and liability if for any reason there is a failure.
This is why when people do experiments that are against a manufacturer’s specification they add a disclaimer as such. Otherwise they could face potential liability.
So I would advise anyone to personally follow manufacturer’s safety recommendations even if it might well exceed minimal safety specification.
You might think that. But ultimately you need to read the manual regardless if the supplied plugs seem to contradict what is said.
The simple fact you should follow Manufacturer’s recommended specifications regarding safety. Even if your better educated to “know” better due to education. You should also not advise people to go against manufacturer’s safety recommendations without a disclaimer or risk liability as well for contradicting a manufacturer’s specification.
I disagree on this though. If the cables are supplied with 2 Pcie connectors on one cable, one should safely assume that they are speced to run at full ATX capacity. If you could not pull 150W on each, it would not be an ATX power supply anymore , hence the manufacturer would be liable for any faults that may happen, which of course is a situation they would not put themselves into.
However, I’ve made my point on this. It’s not black and white on this case, but OP may decide for himself on the information given here if he want to spend money on a new PSU for peace of mind, but it is not required for his application. Most non OC 4090 even comes with an adapter with a 3x8Pin adapter. With 3 cables you are running within ATX specs, that is non-arguable.
I will not comment further as this thread is now way off topic.
Yes you can disagree with the manufacturer and accept risking going against what is printed in “Black & White” in there manual. And yes it may indeed be very safe as the manufacturer maybe being extra cautious to avoid liability should a potentially unlikely failure occurs.
Making assumptions is a risk in itself.
The manual supercedes what cables are supplied.
If you want a clearer idea on this look at an Elevator. An Elevator might be rated for 10 people using a base that each person on average say weighs 200lbs. That means the Elevator is spec’d at 2000lbs. However the Elevator is tested to 20000lbs vs a Lifting device not used for lifting people is tested iirc only to maybe 2.5 rated capacity in this example a freight Elevator tested at 5000lbs.
Even though we might know the true tested capacity the manufacturer is higher than the rated capacity. Advising people you can safely exceed the rated capacity might be true. It would be unwise to endorse doing so.
You can always post your opinion why you personally ignore the manufacturer’s recommendations citing examples that support your reasons. But it is an opinion that can void warranties and manufacturer’s liability should a potentially unlikely failure occurs.
So both you and @Sargon have indeed made your points for and against following manufacturer’s specifications. To which in this case is Corsair and Nvidia recommendations to not daisy chain the 12vhp connector.
So yes the Op has the information to make an informed decision whether to follow the manufacturers’ recommendation with there products or to ignore them in favor of other information presented.
To give an off the wall example. I parked beside a sign that said I could park there; however an overzealous Bylaw officer issued me a ticket because the law supercedes the sign due to a Fire Hydrant is within 10ft of the sign.
Needless to say was not impressed with the city making this situation. More interestingly often Handicap spots with meters are often beside Fire Hydrants. Which of course the bylaw meter maids do not risk ticketing those spots.
That’s a rather strange comparison though, tbh. I will politely agree to disagree on this specific use case regarding the daisy chain being a safety issue though.
However, what have also been stated very bombastically by @Sargon in this thread, is that even 3/4 cables are bad for OP and may cause overload. Read: “OP should get a new PSU to be safe”. This is his own opinion on the topic, it even contradicts Nvdias own FDS sheet and should be called out as false information. I will put a link to it here once and for all.
To sum it up, 3 cables are completely fine, using a daisy for the 4th is something you should only consider if you know what you are doing and know that your PSU and cables are up for it. I was trying to give an educated approach on this to OP so that no needless concerns of safety come into play, which would lead to spending more cash for nothing. But it seems like this kind of information is not welcome here.
Sure you disagree with the manufacturers’ recommendation against it. Based on other manufacturers’ component specifications.
While I may believe it may not be a safety issue. Ignoring a manufacturers’ recommendations on using there product can void warranty liabilities and liabilities for “improper use”.
If you want a more direct comparison. Space heaters often state not to use extension cords. This stated for safety reasons.
That being said a heavy gauge extension cord used for construction typically 12 gauge. Could be used safely. However if anything happens the manufacturer is safer from liability as the end user ignored the instructions.
You said key words “if you know what your doing” and are willing to ignore the manufacturers’ instructions of use and possible consequences; ie void warranties.
There is nothing wrong with posting opinions with supporting links to specifications as you have. However as stated best to at least post a disclaimer this advice is contrary to the oem’s instructions of use.
This IS oem’s instructions of use. He will not be voiding any warranties by using only 3 cables, leaving the 4th connector empty. Regarding daisy, I agree. It is an active choice which in worst case could void the warranty, even though highly unlikely based on his HW, even more unlikely that this could be traced to the use of a daisy. I should maybe have been more clear about that one.
Where did I advise people to do so? - The opposite is true, I told every user with a 20cm width case (like me) is out of spec, regardless of a technically possible carefully applied narrow bending. Which causes potential warranty issues in case damage. That´s what I told, just look above. The thread opener has a bigger case, which we didn´t know in the first place, so no issue with this.
At least, this discussion shows the 12VHPWR connection is on the edge.
I illuminate the problem with my solution, a picture from outside into the case:
You didn’t but you likely noticed people imho overreacted to you posting the specification. Simply because the Op’s case is bigger than 20cm wide.
All Sargon was quoting that while the advice may have supporting specifications to maybe able to run 3 pciX cables and/or daisy chaining them might be done safely. Doing so is against the manufacturers’ instruction.
Imho You and Sargon have both had similar reactions when Quoting manufacturers’ specifications on recommended “safe” use.
Therefore I registered for the CableMod 90° connector , another shorter cable I would like to order, but all out of stock everywhere, beyond some scalper offerings.
edit: photo taken during mounting…
I think there may be some misunderstanding there. I didn’t say it couldn’t be run with 3 cables, and in fact the link I posted and the quote I posted from that link states as much. My only point was about the daisy chaining being against Corsair’s recommendations.
Note that I have the same Corsair PSU as the op, and I’m running all four individual cables on mine. I’m not sure where the idea that OP would need to buy a new PSU comes from. The power supply comes with enough cables to plug in all four into the adapter without need for daisy chaining. The PSU has 6 PCIE ports. If he needs to buy additional power cables for some reason, they’re not expensive.
It shouldn’t be difficult for OP to cable it according to Corsair’s recommendations. I’m mystified as to why there is so much resistance to the idea of cabling it the way the manufacturer says to cable it.
