GPU overheating in riser

[JKKGBE]

Hey, so I've encountered this problem today. Had a gaming PC with 980 Ti, started mining zcash and wanted to make a mining rig out of it, so I bought some GPUs. So first rx 470 came in today, I've flashed it and all works fine, mines Ethereum while its in a molex riser alright. Problem arised when I took 980 Ti out of motherboard slot into a SATA riser (connected it on the same cable with rx 470, and into same PCIe lane it was before). When I run zcash miner the card mentioned doesnt reach the volts it reached before and uses most of the time only 160W in hwinfo instead of 215W, but sometimes it reaches that for a sec, and in 30 seconds reaches 90*C with fans on 100% and shuts down or throttles in time at 85*C. Sol/s reduced. 470 doing its thing not minding. Switched riser - nothing, switched cables - nothing, switched back to motherboard slot - 980 Ti back to normal. Any clues? Couldnt find any info on this matter. Not using those included SATA to Molex cables, only PSU cable.

PSU: Bequiet Power Zone 1000W
Motherboard: Gigabyte Z68AP-D3
rest irrelevant I think

[1714126567]

1714126567

[64dimensions]

Usually when this happens to me, this means that I forgot to start MSI afterburner or whatever software you use to setup the GPU parameters prior to using the card for mining. For me this results in the card is running all out on the built in memory/core frequency defaults, voltage offset.

[JKKGBE]

But it only happens in riser. And I have Afterburner set to "start with Windows" and "Apply on system startup" turned on. Same settings same everything, just overheats while in riser, but why if the voltages and wattage are same or lower? Right now I have it running in my MB but it's covering one lane so it's not ideal.

Thanks for input nonetheless.

Edit: Noticed that my rx 470 gets to 75*C in riser, while it was 60-65 in MB, but nothing so extreme as with 980 Ti. Can it be the risers? Bought 2 different versions but from same vendor. Or may it be the board?.. Any ideas what I could do?

[Heimer]

Try different riser or heavily undervolt GPU

[JKKGBE]

Yeah but undervolting = less Sol/s in this case most probably. I'll buy riser with PCI-e power input from another vendor and see. But if anybody has anything else please reply.

[JKKGBE]

Dont want to start new thread.

Anybody know if this is normal, that when I don't connect display to RX 470 that's in riser, then it heats up to 75 degrees C with fans 90% and I can't monitor it in software, and if I do connect the display to it then it's cool 60 degrees with 60% fans? Do I need to dummy plug it so it doesnt do that?