Can I use a GTX 780 with only the 6-pin power connected?

[tviceman]

Both power connectors need to be connected. You also need a better PSU for that video card.

Running my 4770k @ 4.2ghz and gtx 780 @ 1189 / 6900 with a 450 watt Silverstone PSU (same PSU Valve used in their steam machine prototypes).

EDIT: I don't know much about the OP's particular PSU though, so maybe his isn't as reliable as mine.

 

[vasdrakken]

Just a note on the pin requirements. First if the card requires a six pin and eight pin it will not boot without both. I have forgotten to plug them in and wondered why my system was not booting. Basically unless you start modding the card here what the power draws are based on and internal circuitry requires so much power to initialize.

No pin means the card draws less than 75 watts and draws it all through the PCIe bus.

One six pin means the card draws up to 150 watts, 75 watts over the PCIe buss and up to 75 Watts over the six pin connector.

Two six pins means the card can draw up to 225 and needs a bare min of 150+ watts or it would only come with one six pin connector. The added cost of the electronics for that second power line cost enough no company would add the second connector if it was not needed.

One six pin plus One eight pin can supply up to 300 watts, which tells you that the eight pin alone is supply 150 watts by itself, which is as much as the six pin plus the PCIe express together are supplying.

You might get two six pins to work but I sure as hell would never use that configuration as it not what the spec calls for. 225 vs 300 or 75 watts short. The card might only draw say 250 watts but likely there will be issues. If the pegs that are missing are the grounds your insane since 250 watts that is not grounded is just a bad idea.

Though if you just don't plug in the eight pin the system won't boot so there really is no question as to do it or not.

 

[3DVagabond]

How many ways are there to say no?

 

[Smoblikat]

Will I? The card requires 250W, meaning ~21A on the 12V rail. The PSU provides 33A, and apart from the GPU, all I have in the machine is one SSD (usually under load, has OS/games on it), one HD (just storage), one DVD drive (rarely ever used), and 3 or so low power fans. Even if nVidia was conservative with the power requirement figures (which I doubt), it looks like I have plenty of headroom there.

You MIGHT be able to get away with using that card for a short time with that PSU, but it will burn out quickly. 6 pin PCI-e is rated for 75W, and 8 pin is rated for 150W. A single molex is only rated for 35w, so even if you run a dual molex to 8 pin you are still trying to pull at least 150w from a source that is only rated for a MAX of 70w. Get a good 550w - 650w PSU for your rig and call it a day.

For reference, my 3770K machine has a 1300W platinum PSU, the X6 rig has a 750w silver, and the dual CPU one has a 1000W gold PSU.

 

[Will Robinson]

Its no good pairing a Penryn dual core with a 780..its just a waste.
Time for a platform upgrade.

 

[Subyman]

How many ways are there to say no?

Lol. I'm sure someone will think of another way.

 

[ocre]

But it seems like a catch-22. "Sell the 780 GTX, buy new motherboard, processor and RAM . . . " Graphics card? The OP should also consider keeping the card, selling or recycling her old CPU-mobo-RAM combination, and building a Haswell system with a motherboard that either matches or foresees her needs. This in addition to the PSU.

I hate to see people facing these sorts of crossroads, although I do it all the time. But "all the time" means that I target household hardware for upgrade, schedule the purchases over a several-month time-horizon and take my time putting it together. If a person isn't computer-obsessive, situations like this hit you without warning.

I think he is off to a good start if he wants to have a very nice PC. The 780 is one of the most important and expensive components. First he will need a PSU and then he could at least game on it while he saves up for a haswell combo. MicroCenter has some amassing deals. You know he might could pick up a good deal on used HW. ivy bridge or sandy 2500/2600k or 3770/3570k. Compared to the GPU, these things could be scooped up rather cheaply.

This is a good place to start, if he decides to build him up a powerful gaming PC. But first off, get an appropriate power supply

 

[PrayForDeath]

Its no good pairing a Penryn dual core with a 780..its just a waste.
Time for a platform upgrade.

Link to source? That image doesn't really say anything (not saying you're wrong, that CPU is ancient)

 

[OCGuy]

I'm sure this has been said more than once, but you need a new PSU before you can use that card.

You also want a new CPU.

 

[cdoublejj]

There is nothing on that socket that will properly run a GTX 780. Remember, you're talking about one of the fastest video cards ever made, and a socket that was abandoned by Intel in 2008. Your chip was introduced in January 2008. I remember it fondly...I bought it the month it was released. I ran it with an 8800GT, released in Oct. 2007, which had 1/6 the power of a GTX 780. That was a pretty good match for the e8400.

So, as to the minimum system you'd need to support the GTX 780...I'd say an Intel i5-4570 plus a B85 motherboard, ideally with 8GB of DDR3 RAM. So that's roughly $200 for the processor, $75 for the motherboard, and $75 for the RAM. The total comes to $350, and I'd say it would be money well spent.

an overcooked q9550 with ddr3 is on par with first gen i5s. an overlcoked Xeon equivalent at 4.2-4.6ghz is even more powerfull (if your using socket 771 to 775 adapter) One user on overclock.net even test a gtx780 on a q9550 with a moderate overclock on ddr2 and little bottle necking and good frame rates.



I have a 850 watt PSU with 4 of these connectors,

so what i have is 2 150watt 6 pins with 2 wires tacked on just incase the GPU checks for 8 wires.

I want to know if the GTX 780 will post and run with 6 capable 150watt pin connectors. (say my those little extra wires broke/fell off all 4 connectors and i'm down to the 6 pins.)

 

[toyota]

how does someone just get a 780 as a gift out of the blue? that really makes no sense. the person buying that would have to have had some reason to think you wanted that.