Annoying basic question about GTX 1080 ti GPU power supply

So, scored my new (previously loved, hopefully not mined to death) 1080 ti, but it came without cables so I’m trying to figure out which ones I need, or if I need to upgrade my PSU. Lockdown is a bitch: no shops to go to for advice.
Nvidia specs (and eyeballing the card) say I need 1x8 pin connector and 1x6 pin connector into the card, but my PSU only outputs 2x6 pin (enough watts tho, 620)
I’ve found a 6-to8 connector, but for the 6-to6 can I use a 6-to-8 pin connector and lop off two pins, and if so which ones?
I would prefer not to fry my card obvs… …:slight_smile:

Hm, a bit difficult to understand, but yes, you can use a 6to8 converter for the 8 pin, and for the 6 pin you just connect the 6 pin, no need for a 6to8 there.

ok, but I only have 6 to 8’s so the question is: Can I use 1x 6 to 8 and 1x 6 to 8 with the obvious pair cut off? And if I cut them off do I need to short them?

Now thats odd, sure they aren’t detachable and you have a spare 6 pin in a box?
Or one cable is tucked in underneath other hardware?
Computer builders often like to keep things tidy.
What PSU do you have?

Edit: Just understood you image, that is a detachable cable and is 6->8 converted. So I would rather get a 6 to 6 cable if you don’t have that lying around. I would not cut it off unless you google it and find that it is a “normal” procedure and that you can make sure it doesn’t short circuit anything…

master cooler 620 m2 PSU.
Yeah, I guess I’d better have a dig around but the only spare PSU cables i’ve seen inside aren’t 6 pin or 8 pin…
My current feeble GPU takes its power from the pci slot.
Saw a video by DerBauer showing high-end GPU’s running on only 2 or 3 (out of 16) of their PSU connections without problem… figure I could miss a couple, but don’t know which ones to snip…

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Yeah, don’t want to fry my card…
Nvidia have nothing to say… no humans available.
GTX 1080ti seems to be unique in its 8+6 pin input. Infuriating.

If your psu has 2x6 pins, why not plug one of the 6 pins directly in and the other with the 6 to 8 converter for the 8 pin input?

Quick search only, found that and it discuss power reqiurements. Your card needs at max 250w so it needs more than just a eight pin. But in theory you can connect only the eight pin and have a go while you wait for the six pin cable to show up. The eight pin can deliver 150w so that should suffice for 80% load or somehing. (power consumption isn’t linear with load)

But not getting enough power can make computing innacurate and cause buggyness and drawing too much from the psu can harm it apparently (if I understood it correctly)

That’s all I can say and I am already in deep water, so good luck and if you feel adventurous then be carefull. Don’t want you to break anything.

Your 650 psu should be strong enough as the 1080 ti has 600w as minimum for system. (but not if you overclock your cpu, has two gpus etc)

6+8 is not unusual by the way, but only used for cards with high power needs. (top performance cards like ti models, oc models and/or those with multiple fans at the same time)

All that said, I recommend connecting both cables. (But being who I am I know I couldn’t resist trying… :expressionless: ) So read up, be smart and Good Luck!

Edit: by the way, using a 6 pin out from the psu with a converter (in your case the 6 to 8 cable) is fine! No worries there.

Thank you…

So are they all just power, or are some of them ‘sense’? (ie sending state info to/from the card, and if so can the lack of these jeopardise the card?)
My next problem is that all the cables I just bought are the length of my thumb. Can’t imagine a scenario where they can be used without extensions… what’s the point of their existence? Grrr…

From what I read they are power and ground (return power). Some grounds are also for sensoring.
How the 6-8 is cabled I do not know. But some connector cable are BOTH 6 and 8 where the two extra are detachable (on a separate plastic thing that snaps onto the 6 part) and becoms an 8 IF used, or a 6 if not used… So I presume you can alter your cable… but I DO NOT KNOW!

The short cables are converters. Many PSU’s have undetachable cables and 8 pin is newer than 6 pin, so those need to be split.

Apparently the reason for 8 instead of 6 is to allow more power through thin cables, thus more thin cables, so they don’t run hot. (How Apple let you charge a laptop through a usbc is beyond me as those are thin…)

Edit: by looking at that picture it appears that the two extra are ̶j̶u̶s̶t̶ ̶p̶o̶w̶e̶r̶,̶ ̶n̶o̶ ̶g̶r̶o̶u̶n̶d̶. So read up :slight_smile:

EDIT 2: It’s the other way around, those to apparently are ground, not power. Colored ones are the 12V ones.

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You need to contact the manufacturer and obtain the cables that are supplied with the card. The cables have 5v and 12v rails supplying power the the GPU, along with proper ground leads.If you do not know how to utilize a multi-meter your best solution is to contact the manufacturer and not rely on these forums.

Yeah I recently fried a dvd drive on an old machine I was resurrecting because I used cables that came with a different power supply. A stinkin’ DVD drive! Don’t mess around with this.

I’m trying! :rofl:
I can’t find what the ‘sense’ cables are sensing, and if I need them…

…if I was king of the world: one connector standard for EVERYTHING, esp phone chargers :zipper_mouth_face:

They just register that something is connected :slight_smile:

Do you mean the PSU?
Graphiccards don’t come with power cables.

GPU’s have always came with their respective power adapters, among many other accessory items. Reading your comments you’re just fluffing information to make it sound like you know what you’re writing about. How about you just stop otherwise you’re going to cause this individual hardware issues.

No, they don’t. They MIGHT come with a CD, a bridge for SLI or maybe a 6 to 8 converter, but I don’t think they do that any more since 8 is a new standard now.

Seriously? Do you think a tone like that is OK on a forum like this?
Geez. You must be confusing PSU’s and GPU’s.

The GPU means Graphic Processing Unit and is actually the chip ON the graphic card, but because graphiccard is tedious to type GPU has become the used frase. Also because nobody can buy a GPU without it allready being connected to a graphiccard it isn’t confusing either.
Graphiccards NEVER come with cables to connect to the PSU. (The PSU is the power supply unit, the converter of 220V or 110V to 12V etc for peripherals, but it ALSO have 4 pin and other connectors for the motherboard and the CPU (That 4 pin on an ATX PSU is also 12V if you wondered).
Some PSU’s have cables connected to them, others have cables you can connect as you need. (Called modular in case you wonder) All 6 and 8 pins deliver 12V.

That shit I know.

What the OP asks about is IF a 8 pin connector can be downgraded to a 6 pin by removing two cables.
A 6 pin can be converted to 8 pin with a converter, but CAN you safely do the reverse?

Now THAT shit I don’t know, so I tell him to read up.

But I have built many computers and swapped many graphiccards and used many converters and wondered why an 8 pin convertor basically just splits off one of the cables from the 6 pin and adds that to the two extra pins. Now I know. It is to spread the 12V over more cables to prevent overheating.

But I can not guarantee that all 6->8 convertors are built the same. I would be very surpriced if not, since this is an industry standard, but I CAN NOT GUARANTEE IT. I know I would play with it, but I do not reccomend him to do it. Does that make sense?

So I play it safe, shows him what I am not sure about (memory fades, stuff changes, new standards rises etc) and link to some simple texts to dig in to and tell him to read up.
Even you, coming on here tossing personal comments like that, I try to show respect. I think you have your reasons but I don’t care what they are though, you made sure of that :wink:

But I 100% fully agree that nobody should rely on forums. Read many, study shit, buy books, be adventurous, test shit out, fry some shit and evolve. But respect others.

Pease out.

Here is another example of a 6/8 pin connector.
Most debates around these end with the same.

A 6 pin connector apparently has the option for 3 12V and 3 ground
(But often just uses 2 12V, one ground apparently is for cable detection for the card)

As you can see in that link, people are debating this, I have not spent the time on finding better sources.

An 8 pin connector has 3 12V and 5 ground.
(I have not dug into wether any of these grounds on the 8 is used by the GPU to determine that an 8 pin IS connected or not. It surely could, and it would make sense for it to know what is connected, but if you want to know then search deep and wide and please post here just for the sake of contributing to the knowledge base)

You can see that power cables have color and the ground are black.
But many cables only use black because many custom builders are keen on a clean aestetic where neon lights and led lights inside the case shall not light up the cables.
“8-pin only has three 12V wires and 5 ground wires.”

BUT all that said, OP should get a proper 6-6 cable (And in the right length… :smiley: It didn’t occur to me in te beginning that he was holding up a 2" converter. Hopefully he’ll find a full length cable that came with the PSU.

Here I found a schematic drawing of the layout. Note that the top one is wired differently, but does not fit into the graphiccard, so it is not relevant for the discussion as we are talking about PCIe connectors.
"As with later versions of the ATX PSU standard, there is also no −5 V rail. "
Comment found here:
I guess that’s what @bandaid was referring to.

I’m not confusing the PSU. Power cables molex/sata to 6 or 8 pin adapters come with my cards.

The fact still stands that the OP ought to contact the respective card support/forum. You can get the nvidia schematics online, but every one of nvidias pcb vendor is going to have different layouts. The nvidia schematics are baseline requirements for the card vendors.

True, but they either connect with one 6 pin, two 6 pins, one 8, one 8 and a 6 or two 8’s.
(Or none if entry level)
Pcb layout does not matter, that’s what we have industry standards for.