Quote from: Undefined31415 on December 01, 2017, 08:02:25 PM

Quote from: k3rt on December 01, 2017, 07:20:52 PM

My setup:
- x6 GTX 1070
- 1600 Watt PSU with x6 (6+2 and 6+2), x5 (stuff with bunch of molex and SATA adapters);
- x6 risers with 6pin
- So far tried to put one of x6 6+2 to power each GPU, use of of SATA adapter to power the 1 riser

Problem:
- It looks like SATA adapters would sometimes try to melt, because when I power on the PSU - it would shut down immediately (I even smelled burned plastic once).

Possible solution:
- Can I just use both 6+2 adapter of each cable, and just put 8pin to power GPU, while use the other 6pin with 6pin extender to power the riser? Will the 6+2, 6+2 cable handle this?

See this image for what I mean:

P.S. Just to be crystal clear: 1 SATA --> 1 riser seems to be fine. But once I try to use 2 SATA on the same cable to power 2 risers (1 SATA to each riser) - the rig power would sometimes not start, and auto halt. I have only 5 SATA/Molex cables vs 6 (6+2, 6+2) cables - so I am 1 cable short for powering 6th riser.

If you smelled burnt plastic, you have probably damaged one or more connectors on your PSU. Since we're not there to judge, we don't know if that damage is likely to cause problems or not, but I just wanted to mention this first.

Anyhow, you should definitely be fine using the PCIe power cables in the way you described*, powering one 8-pin connection to a card, and a 6-pin riser. In theory, you'd be fine loading both 6(+2) connectors on the same cable, but only loading one 8 pin and a 6 pin is obviously a safer bet.
*Under the assumption that you have decent-quality 6-pin extenders.

The SATA-spec is for a lower current than 4-pin molex connectors and PCIe connectors. Powering multiple risers from the same line of SATA connectors is not recommended, if you're even planning on powering your risers with SATA power at all. Additionally, 4 pin molex connectors seem to handle going over-spec much better than SATA, so if 6-pin PCIe connectors are not an option, try to use molex adapters.

I'm not sure what motherboard you are using, but have you considered plugging one card directly into the board's physical PCIe x16 slot? (Of course, on many boards this removes access to a PCIe slot directly below...)

I currently am in the process of building a nearly identical design, I ordered an EVGA 1600 T2, which has 9 VGA slots, which can each power an 8 pin, plus 6 pin, and I plan to go with GTX 1070 TI's which will take the 8 pin, and risers that support 6 pin, thus having each VGA slot power one Card and riser each,

Suffice it to say, but I will be following this thread!