4-pin to 6-pin molex adapter only has 2 12v wires?

treacotton · Feb 26, 2016

Hey everyone... I am looking to power an nvidia 9800 gt and I am using a PSU without a 6 pin connector. So I bought a molex to 6-pin connector which has of course 2 molex plugs going into one 6-pin plug.

This adapter has all of the 6-pin connections active.. top 3 are 12v and bottom 3 are grounds. 2 of those 12v wires are splitting from one of the molex connections.

After buying this, I found that I already has the exact same adapter... the only thing is with the one I have already, it only has 2 12v wires and the 2nd pin on the 6 pin side is unused. It also has 3 ground wires for a total of 5 pins active.

I have read that sometimes that is the case... but I honestly don't know which I should use or if I should send back the one I bought or what. Whats the difference in a 6 pin that has 2 12v lines and 3 12v lines when it comes to a GPU?

Are these going to be exactly the same or will one give less power than the other? I need some advice on which I should use.

Thanks all.

logainofhades · Feb 26, 2016

Nobody here is going to recommend using those adapters. Get a proper PSU that has the necessary connections already. PSU's that lack them are questionable quality, at best.
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html

treacotton · Feb 26, 2016

logainofhades :

Dude gimme a break... This is not an answer.. You dont know anything about the situation. It is an old pc and you dont know what i am using it for which doesnt require much power. I am using the card because i have it lying around. I have never had a problem with this power supply and there is nothing wrong with using an adapter... If there was then nvidia would not have sent me one of the ones in question with a gts 250 i ordered long ago.

Please, if you dont have a non-smug answer to the actual question at hand.. There is no reason to respond. It is a valid question and deserves a valid answer and honestly I expect a moderator to be more helpful than this.

Math Geek · Feb 26, 2016

it really is not a smug answer. the connections the power supply has on it is based on what it can do and can't do. not having the 6pin connector, tells you that it is not meant to deliver that kind of power to a gpu. the adapter will be trying to provide power that it cannot since the power supply is not intended to provide it.

no one on this site that knows anything about power supplies would suggest using one of those adapters at any time. (myself included) they are simply a band aid trying to be a solution to a sucking chest wound!! you will want a higher wattage power supply to run that card, pure and simple. the missing power connection is all you need to know to confirm this.

good luck with the adapter and if you're lucky it may work, if not... well......

logainofhades · Feb 26, 2016

It was not a smug answer, it was trying to avoid you burning up your system using a PSU that is not designed to work with the hardware you want to use. PSU is the single most important part, of any PC, regardless of its age. PSU is the one item where you don't want to cut corners. Doing so will cost you more money in the end.

IInuyasha74 · Feb 26, 2016

Not sure what the adapter looks like exactly, but if it just has the two 12V lines connected, that sounds awfully dangerous. Because, well, having a ground wire is kind of important.

So use the new one you bought.

treacotton · Feb 26, 2016

IInuyasha74 :

You misunderstood but it's my fault. One connector has 3 12v wires connected to the top 3 pins, and 3 ground on the bottom.. thats the one I bought.

The other has the exact same thing, minus the 2nd pin cause on that one, it is not used/connected at all. So that particular one has only 2 12v+ wires and 3 ground. This is the one that came from nvidia with a gts 250.

So the question is, is there any difference in using the one with 3 12v+ vs the one with 2 12v+, since a lot of 6 pin connectors dont use the 2nd pin, but some do?

treacotton · Feb 26, 2016

Math Geek :

Dude, again, this PSU is probably about 10 years old so I'm not even sure 6-pin connectors were real common back then.

But here's the thing.. there are a crap load of molex connectors coming out of this PSU. Each one has a 12v line on it. A 6 pin connector has 2-3 12v lines on it. If I hooked up 3 drives or other things to the molex connectors it would be giving out the same amount of power as one 6 pin connector!

The PSU is 450 watts and the card is rated for a 400 watt PSU. Considering this PC will have NOTHING hooked up to it really except the MB, 1 HDD, and the 9800 GT... that doesn't scream DISASTER as you guys seem to think.

The GPU's MAX power is 150 watts but it won't use that much of course.. If the thing isn't strong enough or fries something.. BIG DEAL. It is a 10 year old PC that is being used for a personal project and is easy to replace.

So I don't want to hear "buy a new power supply" or "don't use an adapter." I'm not interested in "recommendations" like that.

I only am asking for my original question to be answered and only one of you has even attempted it so lets stick to the adapter question and let the ones who want to help with that talk please.

Math Geek · Feb 26, 2016

ok so let me see if i can explain why the adapter does not really accomplish what you think it does. as you said you can connect a drive to the molex and it works fine. perhaps one on each of 2 different molex connections. a hdd would use about 5w and a dvd writer at full burn is about 20w max.

the 6 pin power connection provides 75w of power to the gpu. so your logic of "If I hooked up 3 drives or other things to the molex connectors it would be giving out the same amount of power as one 6 pin connector! " is not even close to accurate.

combining 2 molex into one 6 pin does not provide the same 75w of power that a 6 pin does no matter how many 12v wires it has on the adapter. the wire is not providing the power, only transporting the power from the psu.

it does seem like you are determined to do this no matter what, so use the newer adapter, let er rip and enjoy whatever happens.

i'm not trying to argue with you rather trying to show you why the adapter is not going to do the job you think it is. but if it's all old stuff anyway and you're willing to lose it all to a possible failure then go for it. a 10 yr old psu won't have the built in protections a new one does so if it goes, it likely will take something with it.

good luck to you.

treacotton · Feb 26, 2016

Math Geek :

I get what you are saying about the card taking 75watts.. I am aware of that. Maybe I'm wrong but if a PSU is 450 watts and has virtually nothing hooked up to it, I think it will have 75 watts to spare... and thats what the GPU would get whether it was coming from the adapter, or being hardwired into the PSU right? As long as the PSU has that much to spare. Yes, the HDD and other stuff wouldn't use as much wattage but the 12v wires are capable of delivering that.

The wires are all thick enough to handle the load, if anything I think the GPU would just be underpowered. I have had experiences in the past with underpowered PSU's and what happened in that case was the PC would just turn off and then turn back on a few seconds later until I replaced it with a stronger one.

Like I said, I may be wrong but I don't think having too little power will cause a power surge and damage any components. I'm willing to take that chance with this application and I have a 2nd 9800 gt if I need it.

And like I said... honestly, if this WOULD NOT work at all... if it was impossible and not feasible to use an adapter... then why would nvidia package it with their GPUs?

logainofhades · Feb 26, 2016

Because people use junk power supplies. Just like recommended wattage recommendations are higher than what is really needed, if you used a proper, quality, unit to begin with.

treacotton · Feb 26, 2016

logainofhades :

You're a pompous one aren't you?! Once again you speak out of assumption.. and you know what they say about people who ASSume. You know nothing about my power supply other than it doesn't have a 6 pin connection and its 450 watts. You think it would have lasted 10 years and STILL be working if it were junk? You probably do, refer back to my first sentence right here. You don't know the brand name or rating or anything else about it. Seriously dude, check your attitude. Why are you even here if you don't want to actually help people without talking down to everyone? or is that why you are here?

These questions are rhetorical cause I could really care less. I have better things to do than to come back to this thread any more so I won't.

To those of you who actually made an effort to be helpful (which is everybody except logainofhades) thanks anyway.

To the rest, you know where to stick it.

IInuyasha74 · Feb 27, 2016

@Math Geek: I might be miss understanding you, but if you are trying to say that a Molex connnector tops out at 20 W of power, that isn't accurate. Molex, the company that actually created and maintains the standard rates the connection with a max of 5 Amps over the 12V rail:
http://www.molex.com/molex/products/family?key=standard_062&channel=products&chanName=family&pageTitle=Introduction&parentKey=power_connectors

That would mean the connector is technically capable of 60 W going by the connection specifications. That is also why the adapter has two Molex to one 6-pin connection, because one by itself isn't rated to carry more than 60 W of current, and falls just short of being able to able to handle it alone.

treacotton, I do understand what the others are trying to say, as PSU safety is a key issue to a lot of users and you would be better off with a more modern PSU. However, you are also using this to power an older system and seem confident that your current PSU can handle it. It might be able to. You do need to check the number of amps the PSU supports over the 12v rail to ensure that it can take the combined load of all your devices connected via Molex at the same time, as most power supplies have a single 12v rail which is shared by essentially everything. If it has 15+ amps available on the 12v rail, then I wouldn't be concerned with and would go ahead and use it.

As for which cable to use, the newer one sounds better to me, but it will probably work fine with either.

logainofhades · Feb 27, 2016

I am actually quite the cheapskate, and will cut corners where I can to save money. I just learned the hard way about not using a proper psu. It died and took a motherboard and processor with it. Sorry if I am trying to save you from the same fate. Old PSU's, such as that, likely don't have the protections of a modern quality unit.

Math Geek · Feb 27, 2016

IInuyasha74 :

my response was to his reference to being able to use multiple moles connections to power hdd's and optical drives. the numbers were in reference to what those devices use and not what the molex is capable of. so his statement that a 6 pin connector won't use more than a couple of these drives was not even close to accurate as a 6 pin can use up to 75w.

it is also true that newer molex connections can be up to 5 amps but a 10 yr old psu molex would still be on the much older 3 amp variety since it was never intended to power more than a dvd drive at the rough max usage of about 20w. best guess would be 6 amps from the combined 2 molex connectors from this old psu (can't be sure since there is not model number quoted to verify info). this would probably be enough power assuming the psu can actually give that much power to the gpu. again not knowing the model can't be sure of 12v specs nor the rest of the system to know other 12v needs.

a new psu with the 5 amp molex connectors would be better able to handle this type of adapter but i still don't suggest them considering the fact that as we know these cheap crap psu's don't provide anywhere near the power they claim to. so the included adapter is provided with these newer psu specs in mind and not a very old low budget unit.

a 450w psu with no 6 pin probably only provides 16-18 12v amps and is closer to a 250w psu than a 450w psu. this is what we are hoping the op will understand. i think he does now but i also think he is going to try it anyway

i have done a few tings myself that were not completely acceptable on my own stuff as well. i don't suggest it to others but when it is my own and i accept the possible consequences, then why not. may learn something

IInuyasha74 · Feb 27, 2016

Ah okay, that makes more sense. Lol yea, drives are usually between 5-20W (excluding low-power SSDs), with most coming in at around 10W, so yea it would take half dozen drives to hit the same amount of power that a PCI-E 6-pin connector can use.

Hopefully he doesn't have any trouble with it, but hard to say.

PreevBR · Feb 27, 2016

Eh, had to say...
Just do some search on google and you will see there's a reason why most of the people doesn't recommend using these adapters, and you are pretty lucky if your power supply lasted 10 years already, which is already in a dangerous place, because depending on your combined wattage usage and temperatures your PSU had, it will die sometime soon and as people already said, chances are that it will take other parts too, and that's the main reason people invest into good quality power supplies.

So an advice, if you have money to buy a new (And good quality) power supply, do it because it will make your computer last longer.
Also, you did not post your power supply model/specs, it would be a great info (So we know for sure your power supply isn't the so-called time-bombs i.e Tier 5 power supplies).

Math Geek · Feb 27, 2016

in the end it seems he simply has a bunch of older parts sitting around and wants to put together a frankensystem. so long as he is willing to risk the parts and does not actually need the pc for anything important, giving it a shot is not that bad i guess. i'd probably do something like that myself just to see what would happen. however i also do not suggest to others to do anything so risky. it is relative to the situation. i'd hate for someone to come back and say the site gave bad advice and his house burned down...

he fully understands the risks now and won't go into things uninformed. knowing that, our work here is done

just in case though, could you turn a camera on when you put it under a high load for the first time for us? could be an early 4th of july display and it'd be a shame not to get it on film

treacotton · Mar 9, 2016

This turned out just fine btw using the adapter I bought. System has been tested under the most load it will ever be under numerous times over the last week with no issues. So in the end, is it true that you can't use an adapter if your power supply is old and not equipped with a 6 pin connector? no! Is it ideal? no.. will it always work, maybe not, but is it certain doom? nope..

Math Geek · Mar 9, 2016

i'm glad it worked out for you.

4-pin to 6-pin molex adapter only has 2 12v wires?

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