6 pin psu with 12 pin gpu

[Ryan.com pc]

Hi guys, i just bought a used gtx 970 for 50$ usd. My power supply is currently a 400watts fsp 6 pin power supply. However, the gpu requires a 12 pin connector. Is it possible for me to continue to use this psu. If not can someone please give me a reccomendation of any cheap and reliable psu. Around 60$

[Jurrunio]

depends on the country of market you're shopping in.

[Worstcaster]

I don't know your price range, but this should help on deciding reliability.

 

 

[Ryan.com pc]

Thanks guys!

[Guest]

4 hours ago, Ryan.com pc said:

However, the gpu requires a 12 pin connector. 

You mean two 6-pin connectors?  I've never seen a GPU with a single 12-pin.

[Ryan.com pc]

Yes i mean 2×6pins

[Ryan.com pc]

Is masterwatt 550 bronze semi-fanless modular psu good? Thanks

[Worstcaster]

18 hours ago, Ryan.com pc said:

Is masterwatt 550 bronze semi-fanless modular psu good? Thanks

I just had my Masterwatt 500 fail on me recently.  I can't say for sure mine wasn't a one off, but you might want to look at some of Corsair's offerings.

[Ryan.com pc]

Oh damn...sorry to hear that. Is it possible i buy a 6pin to 2×6 pin connector?

[Ryan.com pc]

Its 5 dollars in my country, worth a shot?

[Spotty]

3 hours ago, Ryan.com pc said:

Oh damn...sorry to hear that. Is it possible i buy a 6pin to 2×6 pin connector?

No. At least get 2x Molex to 6pin adapter.

 

Best path is to get a new PSU that is designed to run a graphics card with two 6pin power connectors.

[mariushm]

The GTX 970 consumes up to 180 watts by itself. If you reserve 100 watts for the rest of the components, you're looking at 280 watts. Let's say 300 watts as a nice round number.

If your 400w power supply can't provide at least 300w on the 12v output (it will say on the label the voltage and current, multiply those and you have the watts) then adapter cables won't help you.

If you do decide on an adapter cable, get the one with the most wires .. ex get 2x molex -> pci-e 6+2 pins

 

[Ryan.com pc]

Ok thanks

[Ryan.com pc]

The current is 16amps, how do i find the volts?

[mariushm]

It will say on the label ... you'll have 3.3v , 5v , 12v (one or several, may be called 12v1 , 12v2 etc) , 5vSB (stand-by power supply), -12v and maybe -5v if the power supply is old enough

For each of these voltages, the power supply should say on the label the maximum current on that voltage.

For modern computers, the amount on 12v is important, the CPU and video card and mechanical hard drives and fans are powered from 12v.

 

[Ryan.com pc]

Mine is -12v i think

[comicsansms]

16 minutes ago, Ryan.com pc said:

Mine is -12v i think

3 12V rails (18A,16A and 18A).

 

That'll be a pretty nice PSU, but it's proprietary.

What is the model of the computer?

[Dr_badwolf]

On 9/9/2019 at 10:25 PM, Ryan.com pc said:

Hi guys, i just bought a used gtx 970 for 50$ usd. My power supply is currently a 400watts fsp 6 pin power supply. However, the gpu requires a 12 pin connector. Is it possible for me to continue to use this psu. If not can someone please give me a reccomendation of any cheap and reliable psu. Around 60$

PSU CALCULATION!!!!
... is very easy...

WATTS = Volts X Amps

PEAK cpu usage is infrequent: 970 is not THAT... taxing...

you want to look at the peak power of the GPU itself.. (the actual processor.) 

that one = Not 200  watts
the CPU = Not 200 watts

if you plug in a million things you MAY have a problem
but doubtful

Youre fine
the worse case scenario is the PC would crash.
if it does=get a new one
Otherwise... not a problem

RAM LOAD = inconsequential.

IO load = inconsequential 

USB load = inconsequential

This is the official scientific answer.

[Ryan.com pc]

Ok thanks

 

8 hours ago, comicsansms said:

3 12V rails (18A,16A and 18A).

 

That'll be a pretty nice PSU, but it's proprietary.

What is the model of the computer?

Oh I actually bought it used to try and configure it myself. Its actually a workstation and the specs is i7 6700

16gb ddr4 2133 ram

Gtx 970

C236 motherboard.

Ill buy the connector and see if ill work. Thanks!

[mariushm]

The psu is good enough.

It has 3  12v rails, and each of these rails can supply up to that current listed

12v1 :: 18A  (216w)  (yellow)

12v2 :: 16A (192w) (yellow/black)

12v3 :: 18A (216w) (yellow/blue)

 

but altogether through all 3 rails you can't consume more than 400w - you don't get 216 + 192 + 216w

It's like if you use a power strip with 5 outlets - you can plug something that consumes 1000w in each outlet but you can't consume 5 x 1000w in total, you're still limited by the wall outlet to around 1600 watts (you have a safety fuse in your house's electrical panel that trips above some high threshold).

 

The label also tells you some colors, to make it easy for you to distinguish the rails.

This can help you spread the power consumption between components.

For example, one rail will be connected to the 24pin ATX connector (or in this case a smaller custom 10pin connector) , which gives 12v to the motherboard, pci-e slot (up to 60w going to video card), fans and probably also going to molex and sata connectors (there's a dc-dc converter on the motherboard producing 5v for the sata drives)

Another 12v rail is probably going to the 4 pin or 8 pin EPS (cpu power connector), so it would be a good idea not to add the video card to that load

And the third rail is probably going to the pci-e 6 pin connector.

 

So ... from pictures on the internet this power supply basically has 3 connectors only.. 10pin mb, 8pin cpu, 6 pin pci-e ...

It's kind of difficult to get an adapter cable, because you don't have molex connectors to convert to a second 6+2 pci-e connector.

I guess you could get an adapter that converts the 6 pin pci-e connector to 2 x 6+2 pci-e connector, but it's not the optimum way.

 

The best way would be to get one of those pci-e extensions cables, cut the source connector, open the power supply and solder the wires directly into the holes in the power supply circuit board.

For example, take a 6$ extension like this one: https://www.newegg.com/p/N82E16812198018

This is supposed to convert a 6pin pci-e connector to 2 x 6+2 pci-e connectors.

You could connect this directly to your 6 pin connector and it will probably work just fine.

 

Alternatively, you can cut the white connector, open the psu and solder the wires directly in the holes in the circuit board for the voltages ... place one of each yellow wires in 12v1, 12v2, 12v3 ... this way if the video card takes 75w from a 6 pin connector, it takes 75w / 3 = 25w from each rail.

 

[Mattias Edeslatt]

2 hours ago, mariushm said:

The best way would be to get one of those pci-e extensions cables, cut the source connector, open the power supply and solder the wires directly into the holes in the power supply circuit board.

For example, take a 6$ extension like this one: https://www.newegg.com/p/N82E16812198018

This is supposed to convert a 6pin pci-e connector to 2 x 6+2 pci-e connectors.

You could connect this directly to your 6 pin connector and it will probably work just fine.

 

Alternatively, you can cut the white connector, open the psu and solder the wires directly in the holes in the circuit board for the voltages ... place one of each yellow wires in 12v1, 12v2, 12v3 ... this way if the video card takes 75w from a 6 pin connector, it takes 75w / 3 = 25w from each rail.

 

 

How is that a good idea if you not are knowing that you are giving advise to someone that is experienced with electronics and knows how to take proper measures when working on the internals of a PSU. 

The warning labels on the PSU are there for a reason and not knowing what to do and not to do can kill you or get you serious injuries.

 

A good sign if you should do a recommendation regarding open PSU:s is, does someone need to ask "how can I", or "how do I" they doesn't have the proper knowledge to do it.

[mariushm]

I made the suggestion and gave lots of details. He can pick what works best for him.... I'm not forcing him to do anything.

 

I see it the same way as people give overclocking advice here - people could easily blow their CPUs and memory with overvoltage yet you don't see people arguing against such advice here.

 

If he has a bit of brains, he can figure out yellow wires go together with other yellow wires, and black wires go with other black wires. It's not rocket science.

 

If he's smart enough but afraid to open up or doesn't know how to solder, then he can just use the extension cable as is, or go with the power supply to some service center and give the guy a few dollars for some beer or whatever and he'll spend 5 minutes to solder the wires for him and make sure it's wired correctly.

 

also, if i said a thing twice, well my bad,,, sometimes i write a paragraph and then try to phrase it some other way that's easier to understand and forget to edit or remove the 2nd.

 

// When I say the best way I mean it's best way from an electrical point of view,  not from an "ease of use" point of view.

 

If you use an extension cable plugged into the original 6pin connector, you have an added resistance caused by the contacts in the connectors... let's say less than 10mOhm (0.01 ohms) of resistance there.

If the video card pulls ... let's say 150w through that 6pin connector... you're gonna have 4A of current through each pair of 12v+ground .. that's safe, the pins are rated for up to 9A.

But where you connect the two cables let's say you're gonna have 0.01 ohm of contact resistance ... that means you're gonna lose V = I x R = 4x0.01 = 0.04v so instead of 12v, you're already gonna have 11.96v ... which is perfectly fine, as low as 11.75v is allowed.

There will also be P = IxIxR = 16x0.01 = 0.16w of heat dissipated in the pins... so 3 pairs of pins x 0.16w = almost 0.5w of heat are produced where the connectors are joined (if the resistance is that high, in real life it's probably gonna be smaller than 10mOhm)

0.5 watts would result in those two connectors being slightly warm but still sort of safe. If the heat was higher at let's say close to 1w, over time the plastic shroud of the connectors can dry out and go brittle and that could cause pins inside bend or loosen and cause imperfect connections and eventually have random resets or even have the wires short out from touching each other ... but this can take months of use.

 

So from an electrical point of view, it makes more sense to just go directly to the circuit board of the power supply and solder the wires in the 12v and ground holes. Chances are the maker FSP designed this board for several wattages (400w, 500w, 600w etc) and they probably thought some company may want this design with 2 pci-e cables... so the holes probably exist on the circuit board for another cable. It would be fairly easy to add one if you have a bit of talent with the soldering iron.

 

 

[Mattias Edeslatt]

@mariushm Sorry if I came out hard on you. 

 

I know you gave the advise in well being and you are right, that with common sense you come a long way. I get your point regarding other bad advise here on the forum, but killing a CPU or GPU is not as serious as killing yourself by following a advise on a forum. 

 

You gave other good tips, but a word of varning is always good when recommending to open a PSU. There are components that could kill you, if you not are cautious.  

[Ryan.com pc]

Hi i bought the 6 pin to 2×6+2 pin connector. Decided to just conmect it with my 6pin connector. Sorry, im not that well versed in this field....thanks for your help!

[Ryan.com pc]

How can 

16 hours ago, mariushm said:

I made the suggestion and gave lots of details. He can pick what works best for him.... I'm not forcing him to do anything.

 

I see it the same way as people give overclocking advice here - people could easily blow their CPUs and memory with overvoltage yet you don't see people arguing against such advice here.

 

If he has a bit of brains, he can figure out yellow wires go together with other yellow wires, and black wires go with other black wires. It's not rocket science.

 

If he's smart enough but afraid to open up or doesn't know how to solder, then he can just use the extension cable as is, or go with the power supply to some service center and give the guy a few dollars for some beer or whatever and he'll spend 5 minutes to solder the wires for him and make sure it's wired correctly.

 

also, if i said a thing twice, well my bad,,, sometimes i write a paragraph and then try to phrase it some other way that's easier to understand and forget to edit or remove the 2nd.

 

// When I say the best way I mean it's best way from an electrical point of view,  not from an "ease of use" point of view.

 

If you use an extension cable plugged into the original 6pin connector, you have an added resistance caused by the contacts in the connectors... let's say less than 10mOhm (0.01 ohms) of resistance there.

If the video card pulls ... let's say 150w through that 6pin connector... you're gonna have 4A of current through each pair of 12v+ground .. that's safe, the pins are rated for up to 9A.

But where you connect the two cables let's say you're gonna have 0.01 ohm of contact resistance ... that means you're gonna lose V = I x R = 4x0.01 = 0.04v so instead of 12v, you're already gonna have 11.96v ... which is perfectly fine, as low as 11.75v is allowed.

There will also be P = IxIxR = 16x0.01 = 0.16w of heat dissipated in the pins... so 3 pairs of pins x 0.16w = almost 0.5w of heat are produced where the connectors are joined (if the resistance is that high, in real life it's probably gonna be smaller than 10mOhm)

0.5 watts would result in those two connectors being slightly warm but still sort of safe. If the heat was higher at let's say close to 1w, over time the plastic shroud of the connectors can dry out and go brittle and that could cause pins inside bend or loosen and cause imperfect connections and eventually have random resets or even have the wires short out from touching each other ... but this can take months of use.

 

So from an electrical point of view, it makes more sense to just go directly to the circuit board of the power supply and solder the wires in the 12v and ground holes. Chances are the maker FSP designed this board for several wattages (400w, 500w, 600w etc) and they probably thought some company may want this design with 2 pci-e cables... so the holes probably exist on the circuit board for another cable. It would be fairly easy to add one if you have a bit of talent with the soldering iron.

 

 

How do i prevent the power from meling the shroud or cause problems to my computer? Thanks