Strange :| I'm running a full rig @ ~570GHs off a TX850M and she seems cool as a cucumber.
But like I said I bet you did not make the mistake of running BOTH 6pin connectors off of the same main PSU 8pin PCIE feeder (talking about the modular plugs on the PSU itself) Essentially it's a splitter that converts 8pin to TWO 6pin. That is what I was using and that's a big no no. Check your total power usage and feel to see how hot the cables feel at the PSU end. That is where it will most likely melt the plastic around the pins.
I also observed a funny phenomenon where the system slowly overclocks itself. Essentially the resistance on the h-cards at the R02 resistor lowers itself with time. Don't ask me how this happens, but it may be somehow the way I pencil modded them? I dunno, either way I'm hoping that it will remain stable for now.
Anyways, wrong thread for this discussion.