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
Comments
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.
Unfortunately I don't have enough spare motherboard slots.
SATA POWER: 18 awg
SATA: 20 awg
What does this mean?
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.
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
just use 1 card on 1 string
i also used the floppy connector ones since march with no problems but again dont wanna burn anything
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.
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.
The overload happens when you use a sata connector specd at 50W for delivering 80W.
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.