PSA: 2 different types of Sata to Molex cable adapters with USB Risers. 18awg vs 20awg

TruthchanterTruthchanter Member Posts: 549 ✭✭✭
edited September 2016 in Mining
Recently I've made a few orders of USB Risers and I found something interesting with the 470/480 problem with risers powered by sata. There are at least 2 kinds of sata to molex cable adapters being sold with USB powered risers.

1. SATA POWER - These are not safe with 470/480, even underclocked and undervolted (not sure about 8pin cards tho)

2. SATA - These seem safe with 470/480 but only if the cards are underclocked and undervolted



I had the SATA POWER ones burn up/melt on me. The SATA ones still get really hot if they aren't undervolted. However if the SATA are undervolted and overclocked, then they, SATA, will only get mildly warm at most! These seem safe so far.

EDIT: sata power is 18awg and sata is 20awg

Post edited by Truthchanter on

Comments

  • remek4x4remek4x4 Republic of PolandMember Posts: 76
    Thanks for posting :)
  • rolsonrolson Member Posts: 21
    I see there's some markings on the yellow cable of the "sata power" one -does it have the AWG size? What about the second one?
  • adasebadaseb Member Posts: 1,043 ✭✭✭
    Undervolting the RX470/RX480 makes ABSOLULTELY no difference to the PCIe slot power because the same amount of current is pulled because its what powers the memory.

    All you do when undervolting is you are pulling less current from the PCIe 6 or 8 pins connectors.

    Just do it the correct way like in the other thread and power it with either Molex or with the PCIe +12V wires. These SATAs were meant to power hard drives using 5Watts of power and not a GPU which pulls 60Watts.
  • rolsonrolson Member Posts: 21
    adaseb said:


    Just do it the correct way like in the other thread and power it with either Molex or with the PCIe +12V wires.

    That's why I'm interested in the wire gauge - which of these is better to use for building the sata/molex/pcie hybrid.
  • Tbone5660Tbone5660 Member Posts: 75
    Playing with fire... These were used on rx480's only 1 gpu per string undervolted. They looked like this after a month!
  • adasebadaseb Member Posts: 1,043 ✭✭✭
    rolson said:

    adaseb said:


    Just do it the correct way like in the other thread and power it with either Molex or with the PCIe +12V wires.

    That's why I'm interested in the wire gauge - which of these is better to use for building the sata/molex/pcie hybrid.
    None of the SATA are better. Just don't use them at all with your 480. If you run out of Molex just put one GPU inside the motherboard slot
  • rolsonrolson Member Posts: 21
    adaseb said:



    None of the SATA are better. Just don't use them at all with your 480. If you run out of Molex just put one GPU inside the motherboard slot

    I understand not to power them directly. I mean to to cut the 12v away from the sata end of the sata-molex, and splice it into the 6/8pin PCi-e 12v line as in another thread.

    Unfortunately I don't have enough spare motherboard slots.
  • adasebadaseb Member Posts: 1,043 ✭✭✭
    rolson said:

    adaseb said:



    None of the SATA are better. Just don't use them at all with your 480. If you run out of Molex just put one GPU inside the motherboard slot

    I understand not to power them directly. I mean to to cut the 12v away from the sata end of the sata-molex, and splice it into the 6/8pin PCi-e 12v line as in another thread.

    Unfortunately I don't have enough spare motherboard slots.
    Yes you can do that because the PCIe +12V is of better guage and can easily handle all that current.
  • TruthchanterTruthchanter Member Posts: 549 ✭✭✭
    rolson said:

    I see there's some markings on the yellow cable of the "sata power" one -does it have the AWG size? What about the second one?

    WOW nice find! I just looked and both types having markings for the AWG (and other info)

    SATA POWER: 18 awg
    SATA: 20 awg

    What does this mean?

    adaseb said:

    Undervolting the RX470/RX480 makes ABSOLULTELY no difference to the PCIe slot power because the same amount of current is pulled because its what powers the memory.

    All you do when undervolting is you are pulling less current from the PCIe 6 or 8 pins connectors.

    Just do it the correct way like in the other thread and power it with either Molex or with the PCIe +12V wires. These SATAs were meant to power hard drives using 5Watts of power and not a GPU which pulls 60Watts.

    My experiment data says otherwise. I tried my 480 rig with default clocks/volts and underclocked and undervolted with the same sata to molex.

    default settings: very hot wire
    underclock/undervolt: mildly warm wire.
  • TruthchanterTruthchanter Member Posts: 549 ✭✭✭
    Tbone5660 said:

    Playing with fire... These were used on rx480's only 1 gpu per string undervolted. They looked like this after a month!

    How much were they undervolted, what mv?
  • cidmocidmo Member Posts: 446 ✭✭✭
    sad cant use these satas tho, i hate molex with a passion
    cant tell u how many times im trying to connect em and a wire pops out the back
    even have a few i just ripped the female end off
  • mpunishermpunisher Member Posts: 19
    I use SATA on rx 480 and I have no problem , since a month
    just use 1 card on 1 string
  • cidmocidmo Member Posts: 446 ✭✭✭
    @mpunisher i have been doing that too but for the fear of burning up something i stopped
    i also used the floppy connector ones since march with no problems but again dont wanna burn anything
  • rolsonrolson Member Posts: 21


    WOW nice find! I just looked and both types having markings for the AWG (and other info)

    SATA POWER: 18 awg
    SATA: 20 awg

    What does this mean?

    AWG is the standard "American Wire Gauge" - how thick the wire is. 18 is thicker than 20 and should be able to handle more current.

    Looking at Tbone5660's pic, those melting wires are 20AWG too, so I'd be careful with your experiment data - warm cables aren't an especially good thing either.
  • hasherhasher Member Posts: 642 ✭✭✭
    As i've said in numerous threads, just connect 2 risers per molex string, with the molex plugs connected directly to the riser (no SATA adapters!!). I've yet to have any issues connecting my 470/480s this way.
  • muzzy124muzzy124 Member Posts: 78
    a bad molex (with no-name cable, not 18 or 20awg) could be a reason of fire...

  • RabassoRabasso Member Posts: 151 ✭✭
    hasher said:

    As i've said in numerous threads, just connect 2 risers per molex string, with the molex plugs connected directly to the riser (no SATA adapters!!). I've yet to have any issues connecting my 470/480s this way.

    Agree with @hasher I have no issues running my sata cables with my 480 cranking 30 and 31 mh/s, I use one sata output from my PSU to each riser (it takes 2 psu with 6 sata connectors, one cable per riser, not even two) I use 2 PSU with plenty of capacity so they run without fans and are quite efficient delivering the load.
  • Zorg33Zorg33 Member Posts: 220 ✭✭
    edited September 2016
    @Rabasso bit of a confusion there.
    Everyone recommends NOT to use SATA connectors for risers at all.
    You are lucky to have them working, but that is way out of spec.
  • RabassoRabasso Member Posts: 151 ✭✭
    edited September 2016
    @Zorg33 is a little over but not by much, if you plug 2 satas risers from 1 cable from the psu, that is where the overdraw happens and it will burn out the cables, the risers are powering the Ram on the cards, is a constant draw.
  • restlessrestless Member Posts: 80
    Is there a source for claiming that memory is powered from the slot ?
  • hasherhasher Member Posts: 642 ✭✭✭
    Rabasso said:


    Agree with @hasher I have no issues running my sata cables with my 480 cranking 30 and 31 mh/s, I use one sata output from my PSU to each riser (it takes 2 psu with 6 sata connectors, one cable per riser, not even two) I use 2 PSU with plenty of capacity so they run without fans and are quite efficient delivering the load.

    I NEVER said to use SATA cables or the SATA to molex adapters. SATA and Molex are two completely different connectors, you do realize that right?
  • Zorg33Zorg33 Member Posts: 220 ✭✭
    @Rabasso you are wrong.
    The overload happens when you use a sata connector specd at 50W for delivering 80W.
  • RabassoRabasso Member Posts: 151 ✭✭
    edited October 2016
    restless said:

    Is there a source for claiming that memory is powered from the slot ?

    yes read it here, the power draw from the sata/molex connection is constant to the card (that is why the assumption of the ram is being powered from the PCIe slot), using a riser or plug to the mobo. that is why mobo that have 2 molex connections can only power 3 cards max through MOBO otherwise you will fry your mobo because the cards will draw more than spec on the board.

    why do you think RX 400 series needs powering from the risers? my answer is because they over spec it not caring about it because their main market is the gamers, they just have 1 card. We miners are pushing the limits of the hardware compounding the effect with 6 cards per rig.

    @hasher I realize that.

    @Zorg33 do you know what is the draw on that connection? real draw? not cable spec. my cables are cold not warm not hot...cold, in all my rigs.

    Guys I'm not a super techno hardware guy, just like you I read a lot of the info here and decide my best course of action, so far 5 rigs with no problems at all, just passing my conclusions take it or leave it. Don't believe all you read in the internet, just because i say so, is your hardware in the line.
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