About Adapters

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balnazzar

Weaksauce
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I got to run a GTX 1070 on a PSU which just has a single 6-PIN rail, while the 1070 has a 8-pin connector.

Now mates, please don't say "just buy a new PSU". The computer is a workstation having proprietary psu connectors for the mobo, so the only viable option is to use adapters. The 1070 requires 150W peak, PCIe slot provides 75W, I got to feed it the remaining 75.

I could:

1. Use a dual Molex-to-8pin adapter. Will it provide the necessary wattage?

2. Use a 6pin-to-8pin adapter. AFAIK, a 6-pin rail is rated for 75W, so I should be OK (but then why the heck they put a 8pin connector on the 1070??)

Ideally, I'd like to have a molex-to-2pin, but no one makes it.

I'd like to hear your opinion.
Thanks!!
 
I ran molex to 6 pin for 4 years in my tri-sli 8800gtx system. Burning power for days.

A lot of people will insist you shouldn't, but it worked fine for me for years.
 
GotNoRice said:
You shouldn't even need an adapter for this. Just plug the 6-pin cable right into the 8-pin socket. The extra two holes are just ground.
Click to expand...

While technically true, some manufactures will not allow card to power without ground on the other 2 pins
i had a Sapphire 280X and had to mod a couple of adapters for 6 > 8 pin so it would work on pc i had at the time.
 
Thanks for your feedback, guys.

However, I'd really like to hear some elaboration about 6-pin dedicated psu rail VS. molex/sata --> video card.
 
balnazzar said:
Thanks for your feedback, guys.

However, I'd really like to hear some elaboration about 6-pin dedicated psu rail VS. molex/sata --> video card.
Click to expand...

What kind of elaboration are you looking for? You’ve alaready established a new PSU isn’t an option so why even go down that route? It’s not rocket science, if your PSU has the power then it has the power and there’s nothing wrong with using adapters.
 
RamonGTP said:
What kind of elaboration are you looking for? You’ve alaready established a new PSU isn’t an option so why even go down that route? It’s not rocket science, if your PSU has the power then it has the power and there’s nothing wrong with using adapters.
Click to expand...

I just wanted some futher considerations about the two different solutions. For example, I don't know if a rail intended to power hard drives could sustain 75W of continuous output...
 
75 watt + 75 watt = you are fine.

Key issue is, how many amps is the +12 volt rail supplying the 6-pin PCIe connector? Very likely it is capable of providing far more power than you need.

Many are quick to say "6-pin is only 75 watts" etc ... but that is the minimum standard. Nothing about the connector itself controls wattage. That is a function of the PSU.

Two 4-pin molex to 6-pin PCIe may work, but be aware you are asking two 12 volt wires to do the work normally allotted to three. And as you said. Is the rail powering the 4-pins up to the task?
 
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balnazzar said:
I just wanted some futher considerations about the two different solutions. For example, I don't know if a rail intended to power hard drives could sustain 75W of continuous output...
Click to expand...

No one can answer that question for you without knowing the specs if your PSU. I think you're also misinterpreting what rails mean. A rail is not the wire branch coming off the PSU, rails are basically circuit breakers inside the PSU. Most OEM power supplies have a single 12v rail and all the wire branches coming out of the PSU are powered by that single 12v rail. That said, IMO if you already have a 6 pin PCIe connector directly off the PSU, you're better off getting a 6 to 8 pin adapter than you are using a 4 pin molex. You may at some point have a need for those molex connectors where as the 6pin PCIe is really only good for video cards, and you are technically putting slightly less load on the wires even if their power source may be the same.
 
Thank you, you have been quite informative. I think I'll connect it to the 6-pin dedicated cable.

In any case, my PSU has the following specs:

IMG_7680.jpg



Since you two seem to be quite competent, if you have will and time, take a look at another question of mine about power: https://hardforum.com/threads/xfx-p1-650g-ts3x-650w-gold-single-rail.1962505/

Thanks!!
 
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Susquehannock said:
75 watt + 75 watt = you are fine.

Key issue is, how many amps is the +12 volt rail supplying the 6-pin PCIe connector? Very likely it is capable of providing far more power than you need.

Many are quick to say "6-pin is only 75 watts" etc ... but that is the minimum standard. Nothing about the connector itself controls wattage. That is a function of the PSU.

Two 4-pin molex to 6-pin PCIe may work, but be aware you are asking two 12 volt wires to do the work normally allotted to three. And as you said. Is the rail powering the 4-pins up to the task?
Click to expand...

Thank you for your reply. As you may see in may reply to ramon, the PSU label lists the amperages per rail. However, I do not know what of those rails controls the 6-pin cable.

We have to assume it just has 15A. Will it be sufficient?
 
You would be cutting it exteremy close. That’s only 180watt capacity. Better hope it’s one of the 17amp rails.
 
Have you thought about getting an adapter for the motherboard instead? Depending on what model of workstation you have, they might have something on ebay that would convert a standard PSU cables to what you need on the motherboard.
 
RamonGTP said:
You would be cutting it exteremy close. That’s only 180watt capacity. Better hope it’s one of the 17amp rails.
Click to expand...

Going to clarify this. If your PCI Express slot and 6 pin connector are on separate rails, you're ok. Unfortunately there's no way to tell from that image.
 
Uh that appears to be a regular ATX power supply. None of the connectors on that PSU seem to be anything special.
 
Skillz said:
Uh that appears to be a regular ATX power supply. None of the connectors on that PSU seem to be anything special.
Click to expand...

I googled the model number and it looks drastically different than a standard ATX PSU. In fact, It looks like this one runs exclusively off 12v for everything and has rectifiers on the board to adjust voltage to different components.
 
Exactly. It just has two big 12V connectors. Then, there is a 8-pin outlet on the mobo that powers up any other device. It's not like Dell/HP stuff: you won't find any adapter for those units.

This is the very reason for which they are crap cheap on ebay: I bought two kits (mobo, Xeon e5-1650v2 cpu, psu) for 59 euros each.

Now, either I risk or I go for the so-called add2psu, but I'll need a 2-psu capable case.
 
You mother board is non-standard you say? Ok, it has got to go. Instead of fussing and worrying over adapters or compatibility or PSU power ... just buy a new computer.
 
margrave said:
You mother board is non-standard you say? Ok, it has got to go. Instead of fussing and worrying over adapters or compatibility or PSU power ... just buy a new computer.
Click to expand...

Yours was the most money-saving advice I got here! Besides, I didn't think about that.

Thanks! :)
 
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