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Question PCI-E 6-pin to 8-pin GPU power adapters, would you use them? What about with a SATA-to-6-pin combo? Dangerous?

VirtualLarry

Lifer
Aug 25, 2001
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Ordered a few of these. Also previously ordered a few of these:


Would it be "Ridin' Dangerous" to combine the two, and try to run a PCI-E 8-pin GPU off of a single SATA power lead? (Is it true that SATA power leads are made with a thinner gauge wire than molex peripheral leads?)

Anyways, the "HP Power Gaming PC" that was sold by Walmart B&M (of which I gave one to a friend) has a Lite-On PSU, 80Plus-something, that came with two 6-pin PCI-E leads, and not a single 8-pin, or two 6+2-pin, or combination thereof.

I was thinking, I could sell him one of my GTX 1660 ti 6GB GDDR6 cards (takes an 8-pin), to replace the 3GB GTX 1060 GDDR5 card currently (stock OEM version) in that box, that uses a single 6-pin, using one of these adapters, and just not use the other 6-pin. The alternative, is to sell him my RX 580 Nitro+ card, which takes an 8-pin and a 6-pin, and use one of these adapters. (Would an RX 580 4GB GDDR5 be faster than a GTX 1060 3GB GDDR5 card? I think they're close to neck-and-neck, or maybe that's the 6GB GTX 1060 variety.)
 

FaaR

Golden Member
Dec 28, 2007
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I wouldn't recommend running overpowered graphics cards on a OEM computer with weak specs, it could very well work just fine no problems at all, but why risk it? Is slightly higher graphics performance worth a house fire potentially? :p

Maybe consider replacing that power supply with a stronger one that has native 8-pin PCIe plugs, assuming it's not a proprietary ATX power plug on the motherboard... Dell in particular has been infamous in that regard in their PCs, at least in years past. Don't know how they are nowadays.

As for which graphics card is faster, I hear that they have GPU reviews here on Anandtech... :)
 
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Charlie22911

Senior member
Mar 19, 2005
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6 to 8 pin should be fine as long as the total power draw doesn't exceed the specification of the 6 pin, assuming the wire gauge and power supply rating is sufficient as well.
I personally wouldn't trust a PSU that couldn't already accommodate a 1660ti out of the box though.

As for the SATA adapters... no way. Never, heck no. Beyond the obvious reasons, molded SATA cables have been known to catch fire. Throw in some power draw beyond that connector spec... yeah don't. Google "sata molex adapter fire" for some carnage.

Here's a neat example!

EDIT... Wow reddit links are terrible here.
 

thecoolnessrune

Diamond Member
Jun 8, 2005
9,442
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The difference in rating between 6 pin and 8 pin is enormous. 75W -> 150W, a doubling of power delivery. I definitely would not simply adapt from 6 pin to 8 pin. Since the Power Supply in question has it, why not have the guy get a dual 6 pin to 8 pin adapter? Those are 100% legitimate (they're available from ASUS, EVGA, as well as a host of the normal adapter companies like C2G). The 75W + 75W rating of the dual 6 pin connector matches right up with the 150W limit of the 8 pin connector.

If you want to give him an 8 + 6 pin card, you'll have to get more creative. I'd recommend a 6+6 pin to 8 pin adapter for the 8 pin portion, and a dual Molex or dual SATA to 6 pin adapter (I prefer Molex only because as the previous poster referenced, you avoid running into Molded connectors that are really not to be trusted). In either case, the Dual 6 Pin to 8 pin + Dual Molex to 6 pin keeps everything within their wattage handling limits.
 

VirtualLarry

Lifer
Aug 25, 2001
48,832
5,326
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The difference in rating between 6 pin and 8 pin is enormous. 75W -> 150W, a doubling of power delivery. I definitely would not simply adapt from 6 pin to 8 pin. Since the Power Supply in question has it, why not have the guy get a dual 6 pin to 8 pin adapter? Those are 100% legitimate (they're available from ASUS, EVGA, as well as a host of the normal adapter companies like C2G). The 75W + 75W rating of the dual 6 pin connector matches right up with the 150W limit of the 8 pin connector.
You do realize, that there is no difference in current-carrying wires between a 6-pin and a 6+2-pin PCI-E connector, right? The two extra pins are for "sense", and don't carry any additional power. (Look it up, if you don't believe me.) (Edit: This might be an issue of overcurrent limiters on one cable, on a conservatively-speced multi-rail PSU, but nearly all "Gaming" PSUs are single-rail on the +12V, so this is likely, literally, a non-issue. The actual 18GA +12V three wires and three grounds (technically only two grounds) can carry 180W on a single 6-pin, as far as the actual limits of the cabling goes.)


Therefore, the "normal" 6-pin PCI-E cables (talking about from a PSU, with six wires), can easily handle 150W. (Not necessarily so, though, adapted from a single SATA +12V line, that's only one +12V wire and possibly a couple of grounds.)
 
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Magic Carpet

Diamond Member
Oct 2, 2011
3,260
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I wouldn't recommend running overpowered graphics cards on a OEM computer with weak specs, it could very well work just fine no problems at all, but why risk it? Is slightly higher graphics performance worth a house fire potentially? :p

Maybe consider replacing that power supply with a stronger one that has native 8-pin PCIe plugs.
This. Quality power supply should be top priority in ANY computer.

As for the SATA adapters... no way. Never, heck no. Beyond the obvious reasons, molded SATA cables have been known to catch fire. Throw in some power draw beyond that connector spec... yeah don't. Google "sata molex adapter fire" for some carnage.
Here's a nice video on the subject.

Injection molding use high temperature and high pressure. That high pressure can melt the wire insulation. The high pressure can cause the injected plastic to push on the wire in a significant way. If for whatever reason the wires are pushed in a bit too much then it can then move closer under the high pressure soft plastic flow. The insulation melt, and the wire almost touch. With time, any stress in the metal will push the wire throught the plastic slowly, which can bring the wire closer together (had anything on plastic for a while and noticed a dent?). Once it get too close the plastic can't block the angry pixies and zap! Now you have an angry powersupply sending angry pixies down the wires to the arc "welder" and no good thing can come out of that nature improvised welder. As for the crimped one, you could have lifted the plastic tabs on the connector and pulled out the wire. It would come with the sata pins. The connector is really a one piece hard plastic with holes from the back to front to guide the pins. Those holes look more like a tunel than some holes.
 
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thecoolnessrune

Diamond Member
Jun 8, 2005
9,442
375
126
You do realize, that there is no difference in current-carrying wires between a 6-pin and a 6+2-pin PCI-E connector, right? The two extra pins are for "sense", and don't carry any additional power. (Look it up, if you don't believe me.) (Edit: This might be an issue of overcurrent limiters on one cable, on a conservatively-speced multi-rail PSU, but nearly all "Gaming" PSUs are single-rail on the +12V, so this is likely, literally, a non-issue. The actual 18GA +12V three wires and three grounds (technically only two grounds) can carry 180W on a single 6-pin, as far as the actual limits of the cabling goes.)


Therefore, the "normal" 6-pin PCI-E cables (talking about from a PSU, with six wires), can easily handle 150W. (Not necessarily so, though, adapted from a single SATA +12V line, that's only one +12V wire and possibly a couple of grounds.)
Well sort of right? This very much depends on his power supply. A 6 pin only power connector following standards only needs 2 of those 12V wires connected (A 6 pin connector per spec only needs 5 wires). Now lots of Power Supplies (especially the 6+2) will go ahead and connect that third connector, which then makes it equivalent in power output capability to an 8 pin connector, but I don't know his power supply. Especially in a cost-cut-anywhere-you-can system, I personally wouldn't make the recommendation sight unseen that the 6 pin can become an 8 pin. Using a dual 6 pin to 8 pin connector guarantees the needed current wires are in place, regardless of how strictly to spec the 6 pin cables are.

I've got a PSU from a 3 year old Acer gaming desktop from a friend that only has 5 wires connected on its 6 pin GPU connectors. I always find a Power Supply that has dual 6 pin but no 6+2 pin to be a bit suspect on whether the wire gauge + connector could actually carry 150W.
 

SPBHM

Diamond Member
Sep 12, 2012
4,961
335
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AFAIK the sata connector was designed for much lower power, the old 4 pin molex is a much stronger connection for high power, if you have that, 4 pin molex to pcie connector should be the safer route.
 

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