kougarThe poster in question showed a photo of their PSU, and it was clear the PSU was designed with no less than FOUR outputs for PCIe cables. If the PSU is designed to split the load across multiple cables then it's always best to do so. Yes there are standards, but in the real world connectors do not always have good contact, whether that is due to oxidation or because the physical pins no longer perfectly match up. Case in point, I once had a 980X slag an EPS12v connector. It wasn't caused by extreme load, but by poor pin contact that increased the natural resistance until the connector began to scorch. It's always best to divide the load across multiple cables when at all possible just in case, because connectors do wear out over time and with use. When dealing with high-power electronics like a 3090 there's no sense not taking every precaution ahead of time to prevent issues later.
HoggleIt’s always best to use separate cables but a standard does exist. It should be perfectly safe with a quality PSU so while I can see stability issues for an overclock it should be ok at stock.
IntoxicusSo doing some research it seems the 225W rating for the cables might be a misunderstanding. It seems people are getting that from the 150W connector limit added to the 75W from PCI-E.Which if that is the case means you're only getting 150W from an 8 pin PCI-E cable. Not 225W.Which means at 150+150+75 you're 25W short of the 400W power limit using a splitter power cable on a 3 X 8 Pin 3080.The splitter may be rated for 150W at the connections sure. But can the cable itself handle that?Even if the cable could support 225W why push the limits on power connections and cables? It seems like an unnecessary risk for 0 benefit.
KingEngineRevUpIntoxicusSo doing some research it seems the 225W rating for the cables might be a misunderstanding. It seems people are getting that from the 150W connector limit added to the 75W from PCI-E.Which if that is the case means you're only getting 150W from an 8 pin PCI-E cable. Not 225W.Which means at 150+150+75 you're 25W short of the 400W power limit using a splitter power cable on a 3 X 8 Pin 3080.The splitter may be rated for 150W at the connections sure. But can the cable itself handle that?Even if the cable could support 225W why push the limits on power connections and cables? It seems like an unnecessary risk for 0 benefit.A daisy chain cable is rated for 288W. PCI-E Slot = 75W Dedicated 8-pin = 150W Daisy Chain 8-Pin = 288W If you add all that up together that is 513W, so it's fine for a FTW3. See Seasonics diagram and see Jacob doing it too with his FTW3. Seasonic diagram
I'm aware of those recommendations.I'm saying they're wrong. The whole point of my thread, etc is to point out that it seems they should not be making such recommendations.Do you have a valid reference that shows the cable itself is rated for 288W? The *connectors* are still only rated at 150W per connector even if the cable is rated for 288W.What is your source for that? Links please.Some people have been saying they're rated for 225W on forums and it seems that comes from adding the PCI-E slot to the 8pin connector rating. You'll need to provide a valid source for that 288W before I believe it.The daisy chain cables do have a purpose. For 2x6pin connectors on a GPU. Beyond that they should not be used. And when it comes to new builders it is safer to tell them "one cable per GPU power connection" so they don't get mixed up between 6 pin and 8 pin.Also you didn't show everything showing that tweet:
DeliriousPost approved, sorry for the delay
IntoxicusDeliriousPost approved, sorry for the delayAll good and no worries :)Btw I love your quote in your sig! :D "education may be expensive but wait until you get the bill for ignorance" seems to be applicable to the topic of this thread ;)
KingEngineRevUpIntoxicusDeliriousPost approved, sorry for the delayAll good and no worries :)Btw I love your quote in your sig! :D "education may be expensive but wait until you get the bill for ignorance" seems to be applicable to the topic of this thread ;)So did you watch the Der8auer video or not? Because it would clear up a lot of "ignorance" on your part.
IntoxicusKingEngineRevUpIntoxicusDeliriousPost approved, sorry for the delayAll good and no worries :)Btw I love your quote in your sig! :D "education may be expensive but wait until you get the bill for ignorance" seems to be applicable to the topic of this thread ;)So did you watch the Der8auer video or not? Because it would clear up a lot of "ignorance" on your part. I'm subbed with notifications but sometimes one or two good ones slip by me.Oops, didn't notice you already had dropped a link, lol.Right away being reminded of his Seasonic sponsorship makes me cautious. Seasonic is the one with the image of bad advice people are trying to post to "counter" my conjectures and conclusions.Maybe there is not a conflict of interest, but I can't help but take whatever he says with a grain of salt because of the Seasonic sponsorship/ad.Also as always:Just because something can be shown to work in a specific test/experiment/circumstance doesn't mean you should do it or that it's ideal/safe/optimal for normal usage.One of the reason I say one connection per cable is because of the variability in power supplies following specs.Maybe it works with a Seasonic PSU and no other PSU?
KingEngineRevUpIntoxicusKingEngineRevUpIntoxicusDeliriousPost approved, sorry for the delayAll good and no worries :)Btw I love your quote in your sig! :D "education may be expensive but wait until you get the bill for ignorance" seems to be applicable to the topic of this thread ;)So did you watch the Der8auer video or not? Because it would clear up a lot of "ignorance" on your part. I'm subbed with notifications but sometimes one or two good ones slip by me.Oops, didn't notice you already had dropped a link, lol.Right away being reminded of his Seasonic sponsorship makes me cautious. Seasonic is the one with the image of bad advice people are trying to post to "counter" my conjectures and conclusions.Maybe there is not a conflict of interest, but I can't help but take whatever he says with a grain of salt because of the Seasonic sponsorship/ad.Also as always:Just because something can be shown to work in a specific test/experiment/circumstance doesn't mean you should do it or that it's ideal/safe/optimal for normal usage.One of the reason I say one connection per cable is because of the variability in power supplies following specs.Maybe it works with a Seasonic PSU and no other PSU?But his test have nothing to do with his seasonic sponsership. He literally continues to cut wires, measures voltage drops, measures amperage, measure temperature of the cable. Essentially he gets down to drawing 175W of power into only 4 cables, two of them grounded I believe. So power is split between two cables in the end. The voltage drop doesn't change. The cable temperature is also okay, it's within spec which is written write on the cable that he reads off. It's a very scientific approach where he does this with several measuring tools and does it live with furmark running in the background.
IntoxicusSome additional info:Intel makes the PSU specifications and if you search ATX design guide you can find some useful .pdf files that don't seem to say a thing about daisy chain PCI-E power cables. As far as I can tell they're not even in the Intel ATX specifications.The connectors are Molex Mini Fit Jr 5556. They are rated at 13a @ 12v giving us 156W (not 150W, lol.)Even if a cable can support more than 156W the connector will bottleneck that.I'm still hoping an actual Electrical Engineer will notice this and weigh in...I've talked to a friend that isn't an Electrical Engineer but has training, education, and experience close enough. He agrees without question that using both connectors on a Daisy Chain is a bad idea. What is most interesting to me on this topic is people with the education and experience to have a fact based critique of my OP with data and references I can look at. As in an Electrical Engineer or equivalent.Nothing I can find tells me it's a good idea to use a daisy chain on anything more than a 2x6 pin GPU.And when it comes to new builders it seems the safest and easiest to tell them "one connection per GPU power cable."
KingEngineRevUpIntoxicusSome additional info:Intel makes the PSU specifications and if you search ATX design guide you can find some useful .pdf files that don't seem to say a thing about daisy chain PCI-E power cables. As far as I can tell they're not even in the Intel ATX specifications.The connectors are Molex Mini Fit Jr 5556. They are rated at 13a @ 12v giving us 156W (not 150W, lol.)Even if a cable can support more than 156W the connector will bottleneck that.I'm still hoping an actual Electrical Engineer will notice this and weigh in...I've talked to a friend that isn't an Electrical Engineer but has training, education, and experience close enough. He agrees without question that using both connectors on a Daisy Chain is a bad idea. What is most interesting to me on this topic is people with the education and experience to have a fact based critique of my OP with data and references I can look at. As in an Electrical Engineer or equivalent.Nothing I can find tells me it's a good idea to use a daisy chain on anything more than a 2x6 pin GPU.And when it comes to new builders it seems the safest and easiest to tell them "one connection per GPU power cable."I am aware of that PDF and have a copy for myself.I'm not a EE, but the first job as an ME I had was designing EVSE and EVSE power delivery wire harnesses. You have to keep in mind there's a "factor of safety" built in to everything.If a PSU bundled a daisy chain, there has to be a safe way to use it, it doesn't make sense they would risk lawsuits over it. Things are also over engineered for reasons like this, specially at consumer level because again, a good Engineer has to take into account their user base.EDIT: Look at extension cables and how much power the 16 AWG cables have to carry The cable itself in a PC is usually 18 or 16 AWG. Like another user said, it's not the cable that usually is the point of failure, it's the contact ends. The cable themselves have a lot of headroom in terms of how much power can go through them. The contacts, not so much. Bad contact can cause the failure. A daisy chain would split the power and therefore the contacts would be delivering and receiving what they would in a dedicated scenario. So really, the issue is more than likely: 1. A poor quality power supply2. Using sleeved extension cables that ruin the spec of the whole wire harness3. Using custom cables that don't have built in capacitors to clean up the cable noise4. Contacts that have gone bad My point to you is, whatever caused that card to fail on reddit, it's possible the same failure can happen with 3x dedicated if the PSU sucks or the contact is bad (oxidation, deformed pins from constant installs and fatigue, etc) Again, Der8auer did a test making the cables themselves draw more and more power and they still ran within spec.
I think you're missing a big massive point:**If they're not following the specs can you trust a daisy chain cable when you don't know how close to spec it is or is not and in which direction.**If you want to take the risk it's your GPU, your potential for magic smoke, etcWhat I'm trying to say is *don't tell others, especially new builders, to do things that are risky."If you want to take the risk that is your choice as long as no one else gets harmed by it.Don't put that risk on others when we can't even say for sure what wattage the cables are actually rated for and we have a reliable source saying they're not even the correct gauge most of the time.Also maybe Seasonic knows their design can handle it. *If so then what they instruct for their PSUs only applies to Seasonic PSU and can not be given as general advice for all PSUs.*Again sometimes just because you can does not mean you should.Or tell others to do so.Because Debauer can show something in a specific experimental context intended to prove/disprove something tangentially related does not mean it's a good idea for everyday general use.
KingEngineRevUpI think you're missing a big massive point:**If they're not following the specs can you trust a daisy chain cable when you don't know how close to spec it is or is not and in which direction.**If you want to take the risk it's your GPU, your potential for magic smoke, etcWhat I'm trying to say is *don't tell others, especially new builders, to do things that are risky."If you want to take the risk that is your choice as long as no one else gets harmed by it.Don't put that risk on others when we can't even say for sure what wattage the cables are actually rated for and we have a reliable source saying they're not even the correct gauge most of the time.Also maybe Seasonic knows their design can handle it. *If so then what they instruct for their PSUs only applies to Seasonic PSU and can not be given as general advice for all PSUs.*Again sometimes just because you can does not mean you should.Or tell others to do so.Because Debauer can show something in a specific experimental context intended to prove/disprove something tangentially related does not mean it's a good idea for everyday general use.Okay, well I have NOT seen you do anything to prove Seasonic and De8auer wrong or shown any scientific approaches. The only counter argument you have made so far is a conspiracy theory. He didn't make his video to defend seasonic either, it was mostly due to him doing shunt modes and people asking him if it's safe or will his cables light on fire. That was the point of his video. It had nothing to do with seasonic. The image I posted was coincidental.
In case of single rail, the +12V power supply is monitored through one single circuit and there is just one OCP chip configured. The chip gets off as soon as the max amp is reached. But in case of multi-rail PSU, the +12V power source is monitored by multiple OCP chip configured on the PSU. There are more than two monitoring channels and all of them have separate amp rating. These amp ratings are the division of the total output of the PSU.
IntoxicusKingEngineRevUpI think you're missing a big massive point:**If they're not following the specs can you trust a daisy chain cable when you don't know how close to spec it is or is not and in which direction.**If you want to take the risk it's your GPU, your potential for magic smoke, etcWhat I'm trying to say is *don't tell others, especially new builders, to do things that are risky."If you want to take the risk that is your choice as long as no one else gets harmed by it.Don't put that risk on others when we can't even say for sure what wattage the cables are actually rated for and we have a reliable source saying they're not even the correct gauge most of the time.Also maybe Seasonic knows their design can handle it. *If so then what they instruct for their PSUs only applies to Seasonic PSU and can not be given as general advice for all PSUs.*Again sometimes just because you can does not mean you should.Or tell others to do so.Because Debauer can show something in a specific experimental context intended to prove/disprove something tangentially related does not mean it's a good idea for everyday general use.Okay, well I have NOT seen you do anything to prove Seasonic and De8auer wrong or shown any scientific approaches. The only counter argument you have made so far is a conspiracy theory. He didn't make his video to defend seasonic either, it was mostly due to him doing shunt modes and people asking him if it's safe or will his cables light on fire. That was the point of his video. It had nothing to do with seasonic. The image I posted was coincidental. That is not what I said, lol. Don't put words in my mouth like that.Taking things with a grain of salt and extra fact checking due to a potential conflict of interest is what rational and sane people should do. I never ever said there was any "conspiracy" or anything of thay nature.I said it gives me reason to extra fact check the video. I never said it made it invalid.Also I said it's not directly related as it's seeking to prove something else that is tangentially related. And uses 2080 Ti cards. Not 30 series cards.I also said because he can do that does not prove daisy chain cables are safe because a single specifically expiremental case can not necessarily be applied to daily general use.Also he did prove his point, that a 2080 TI doesn't need 3x 8 pin. Which is not what this topic is about....He does have a some valid points that are relevant you failed to mention.That extra pin in the 6 pin above spec can make a difference. *But you can not expect new builders to know to check for this!* And it's a bit ridiculous to expect the average consumer to do the research to know these details and nuances.We're talking about what should we tell new and inexperienced builders to do. Should EVGa and Seasonic be telling customers to use both daisy chain connectors. And if they do should they specific about it only applying to their products and specifying thay they can't comment on other brands products.People are using the Seasonic chart like it applies to all PSUs. Like I said perhaps Seasonic knows their products can handle it. *You can't apply that to every other brand of PSU though.*And to end it off a single experimental result is unscientific. Science requires repeatablility in results for data to be valid. Other people have to perform the exact same expiriment the exact same way and get the same results within margin of error for the results to be scientifically valid.Debauer's video is cool, valid, proves his point unscientifically, and is not scientific without repeatable results and recorded data.I respect Debauer and his content. He does good work and quality content, in two languages no less.He's still human, and flawed like all of us are. He's not perfect, and can be wrong with the best of intentions. "Because Debauer said so" or "Because Seasonic said so" is an Appeal to Authority fallacy.I'm asking for links to specifications directly related to the specific hardware in question.An infographic about AC wall power specs is not exactly relevant. Nor the kind of information I asked to be brought to the table. Neither is the Seasonic chart I've already seen that everyone and their cat has linked at me a dozen times.Link me some manufacturer's specifications and/or engineering specifications on stuff like Molex Mini Fit Jr 5556, PCI-E daisy chain cables, ATX power supplies, etc and we can resume our debate.So far the ATX PSU design guide from Intel says nothing about daisy chain cables I can find. As far as I can tell the cable specs derive from the Molex Mini Fit Jr 5556 Specs.
DeliriousPost approved sorry for any delay
rain2_usaI see all of these arguments about not using both connectors in a daisy chain invalid. There's no reason to have a daisy chain connector capable of having 2 - 8pin connectors if it wasn't meant to be used at the same time. If there was an issue, there would be a warning label NOT to use it under certain circumstances; not buried on a website somewhere. There would/should be a cap/sticker on one of the connectors or similar stating as such. And also remember the days of the 4pin molex. I know I daisy chained the heck out of those in the 486/Pentium days. CD, 5-1/4" floppy, 3-1/2" floppy, tape drive, zip drive, Master and Slave hard drives, Fans, etc. As long as you had the proper wattage PSU, it was all good. My 2 cents.
IntoxicusThe connectors are Molex Mini Fit Jr 5556. They are rated at 13a @ 12v giving us 156W (not 150W, lol.)Even if a cable can support more than 156W the connector will bottleneck that.