power connectors to risers

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mnewxcv

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Just seeing what everyone is using to power their risers. I know some risers can be powered by 6 pin pcie, 4 pin molex, or sata cables directly on the board, while some include adapters. I assume some of you with server power supplies fitted with pcie cables just run direct 6 pin cables to the risers, but what about everyone else? I have heard the sata to 6 pin connector adapters that come with most risers are garbage, and the fact that 6 pin spec is 75w while sata spec is 54w leads to some concerns.

Apparently molex spec is something like 11 amps, or 132 watts, more than enough for a riser. Are you guys using molex to 6 pin adapters? I have personally been using 2x sata to 6 pin adapters (so 54x2 = 108w potential), but am curious to know what everyone else has been doing. Obviously if using a chain of 4 molex connectors, you can't expect that chain to provide 44 amps (528w), but I am using some strings with 4x sata and running 2 of the dual sata to 6 pin adapters, therefore drawing up to 150w from the single chain (2 pcie inputs to risers).

Should I be worried at all? Seems like I'm ultimately not stressing the wires much, but again, I am curious to know what everyone else is using.
 
I will not use SATA connectors under any circumstances. Not only is the power spec mismatched as you indicated, the guage on your average string and/or adapter cable isn't enough to handle that kind of power.

In my rigs, I use 6/8pin PCIe splitters like these and these in conjunction with 1500w PSUs that have 10 PCIe+ 6/8 pin connectors.

In the past, I have used molex -> 6 pin connectors but do not at the current moment. 2 risers per string seemed to work well. I would recommend using the dual molex -> 6 or 8 pin PCIe connector. Those never gave me any issues.
 
atp1916 said:
I will not use SATA connectors under any circumstances. Not only is the power spec mismatched as you indicated, the guage on your average string and/or adapter cable isn't enough to handle that kind of power.

In my rigs, I use 6/8pin PCIe splitters like these and these in conjunction with 1500w PSUs that have 10 PCIe+ 6/8 pin connectors.

In the past, I have used molex -> 6 pin connectors but do not at the current moment. 2 risers per string seemed to work well. I would recommend using the dual molex -> 6 or 8 pin PCIe connector. Those never gave me any issues.
Click to expand...

I'm using the pcie splitters for the cards themselves but not for the risers.
 
Right, i should have been a little bit more specific.

No SATA connectors for even the risers is what i intended to get across!
 
my gripe with the molex to pcie connectors is the fact that some cheap ones have terrible quality and contact, some either lose, or so tight they push the pins right out, in either case resulting in poor contact and higher resistance. With sata, at least it either fits or it doesnt. Neither are ideal IMO, but short of modding, I'm not sure a better solution is out there.
 
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At first I've used the SATA to 6pin but the system wasn't stable and the vegas 56 keep dropping hashes. Current changed it to 2 molex to PCIe and everything stable but will changed it once the pcie splitter arrived.

Btw thanks atp1916 for the link was looking around for quality splitter :)
 
Darksieg cheers mate. You can get those bundled up in packs of 5 on ebay. I have bags of those things lying around - they are fundamental building blocks for any rig.

mnewxcv Agreed about the molex connector design. Their only saving grace is they feed off the 12v lines, perhaps. Just not optimal. Live wires poking out and about in my cases is not cool!
 
Good Info here. I am about to buy risers and I looked everywhere for some that come with NON-sata adapter cables. No luck.
 
I got risers that were pricey but did I not want a fire. They take any type of power connection you might want to use, but you only use ONE connection. I wouldn't power them with an adapter on a high power card.. I power mine with Molex on my R9 270X, but the cards get direct dual 6 pin each from the PSU. I would power the risers with 6 pin directly for sure if my PSU would support it, but I'm just running old hardware to get some use out of it.

I paid $20 for 2 of them, but if you buy 6 they are not any more expensive than the cheapo Mintcell or the like. https://www.amazon.com/dp/B074Z754L...DQ8WA0DQ2HF&pd_rd_w=cj1Tc&smid=A2JG7U147IMRBO
 
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most of my systems use at least a couple sata to 6pin.

I use them only on the PCI-E riser and I plug the 6pin from the power supply directly into the cards' aux power connectors.

I've not had any problem with it.

I use max of two sata connectors per string of four.


I also - more importantly - only buy power supplies with a single 12V rail.
 
i just use strait ribon risers on my board with no extra riser power. i have never had a issue in the MANY rigs i have built but i would use a powered riser for some of the cards more dependent on the mobo for power

notes:
NEVER buy a powered ribon riser. easiest way to fry your card (shotty wire carelessly soldered to one of the pins as for whitch pin is a nice suprise. :p)
alway buy extra risers. they like to come doa
molex to sata adapters can also have issues with igniting.
 
How much power actually goes through the pcie slot/riser? I would have figured most of the power would be going to the 6/8 pin connectors on top of the card.

I'm just using the sata adapters for now for 2 cards... but I got a crimper and Mini Fit Jr connectors so I'll probably make my own harness when I start adding more cards so I can just go straight to the 6 pin molex on the risers.
 
Red Squirrel said:
How much power actually goes through the pcie slot/riser? I would have figured most of the power would be going to the 6/8 pin connectors on top of the card.

I'm just using the sata adapters for now for 2 cards... but I got a crimper and Mini Fit Jr connectors so I'll probably make my own harness when I start adding more cards so I can just go straight to the 6 pin molex on the risers.
Click to expand...
By spec it is supposed to be a maximum of 75 watts through the x16 PCI-E port.
150 wattts max per 8 pin
75 watts max per 6 pin

Of course those 6 and 8 pin connections can be cheated a bit by drawing more when overclocking, but the pci-e slot’s 75 watt shouldn’t be cheated by the manufacturers or you’ll run into the RX480 fiasco where it was originally frying PCI-E slots on motherboards. (It was using more like 85-90 in some tests). Most cards in my understanding are designed to pull less through the PCI-E port for this exact reason. So you’ll see some cards only pulling 50-60 watts in some of the power consumption tests from the pci-e x16 slot.
 
Archaea said:
By spec it is supposed to be a maximum of 75 watts through the x16 PCI-E port.
150 wattts max per 8 pin
75 watts max per 6 pin

Of course those 6 and 8 pin connections can be cheated a bit by drawing more when overclocking, but the pci-e slot’s 75 watt shouldn’t be cheated by the manufacturers or you’ll run into the RX480 fiasco where it was originally frying PCI-E slots on motherboards. (It was using more like 85-90 in some tests). Most cards in my understanding are designed to pull less through the PCI-E port for this exact reason. So you’ll see some cards only pulling 50-60 watts in some of the power consumption tests from the pci-e x16 slot.
Click to expand...

yes, traditionally a card without a 6 pin connector (1050ti for example) will pull more from the slot than a higher powered card (1080ti) that has auxiliary power connectors. The rx480 is a notable outlier.
 
Archaea said:
By spec it is supposed to be a maximum of 75 watts through the x16 PCI-E port.
150 wattts max per 8 pin
75 watts max per 6 pin

Of course those 6 and 8 pin connections can be cheated a bit by drawing more when overclocking, but the pci-e slot’s 75 watt shouldn’t be cheated by the manufacturers or you’ll run into the RX480 fiasco where it was originally frying PCI-E slots on motherboards. (It was using more like 85-90 in some tests). Most cards in my understanding are designed to pull less through the PCI-E port for this exact reason. So you’ll see some cards only pulling 50-60 watts in some of the power consumption tests from the pci-e x16 slot.
Click to expand...


Woah I honestly did not figure it was that much. I figured it was only power for basic functionality like powering any PCIe controller chip or other "housekeeping" stuff. Yeah I'll get rid of my sata connectors then... Thankfully I got the right stuff to just make my own molex harness so think I'll make a harness/spitter that can go straight from the modular psu. how many amps can 18 awg typically carry? I'm finding different results on Google. Does 12 sound right? At least it will give me an idea of how many splits I can do per wire pair. GPU ones are odd though, there are 2 sense lines, so that kind of "wastes" what could be more 12v coming in.
 
Red Squirrel said:
Woah I honestly did not figure it was that much. I figured it was only power for basic functionality like powering any PCIe controller chip or other "housekeeping" stuff. Yeah I'll get rid of my sata connectors then... Thankfully I got the right stuff to just make my own molex harness so think I'll make a harness/spitter that can go straight from the modular psu. how many amps can 18 awg typically carry? I'm finding different results on Google. Does 12 sound right? At least it will give me an idea of how many splits I can do per wire pair. GPU ones are odd though, there are 2 sense lines, so that kind of "wastes" what could be more 12v coming in.
Click to expand...

the amount of amps a certain gauge of wire can carry depends on length. The longer the run, the less amps it can carry. Look online for a chart for amps per length of certain gauge wire. You may find it if you search for car audio stuff, since it is fairly common to use 18 gauge.
 
Yeah knew that, but for most purposes the lengths are short enough that you don't have to derate. Everything I find online varies a lot. Normally I like to go with NEC, but it does not go down to 18awg as 14 is the smallest you can buy for in wall. That's 15 amps.
 
Use automotive sizing charts for amp draw/ length figures.. Everything high amperage in a computer is DC +12v, same as what is in a car.
 
I use every style riser and have had problems with each, but don't use SATA. Having said that, I used a 2 SATA crimped to 6 pin as the 2nd connector on a 1080 for awhile and my house didn't burn down.
 
I think several people in this thread may be missing the point.
It is neither the SATA or MOLEX connector that is a problem,
and in the case my two fires, wasn't wire gauge either.

Its that whenever SATA or MOLEX are involved, 12V necks
down to ONE PIN at the supply. And the modular connector
there is usually what burns up before anything else.

This was a pair of 1050ti's on one SATA peripheral string.
I guesstimate damage was caused by about 13A.

Every piddly negligible load adds up, and those strings will
let you plug in as many as four. Not that you ever should...

Crispy.png


Supply still works, but 10yr warranty is probably void.
 
Last edited:
KD5ZXG said:
I think several people in this thread may be missing the point.
It is neither the SATA or MOLEX connector that is a problem,
and in the case my two fires, wasn't wire gauge either.

Its that whenever SATA or MOLEX are involved, 12V necks
down to ONE PIN at the supply. And the modular connector
there is usually what burns up before anything else.

This was a pair of 1050ti's on one SATA peripheral string.
I guesstimate damage was caused by about 13A.

Every piddly negligible load adds up, and those strings will
let you plug in as many as four. Not that you ever should...

View attachment 53759

Supply still works, but 10yr warranty is probably void.
Click to expand...

I must say, a couple of 1050tis is probably the highest load you can possibly achieve with a pair of risers, since they pull more power from the slot than most other cards. Still, I'm a little surprised. I might get my clamp meter out to see how much my sata cables are pulling through the 12v line.
 
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