Would it be ok if i replace 2*7870 with 2x7850? That would reduce power consupmtion for about 80W or so if my calculations are correct.
Thanks for help , i really appreciate it
mm.
See, GPUs are using not only the power supplied by PCI-E power cables(
http://www.hardcore-[Suspicious link removed]/images/psu/pcie6.jpeg) but also the power from PCI-e slot itself -
http://en.wikipedia.org/wiki/PCI_Express#Pinout, see there are +12V power lines?
So what happened to your rig -
motherboard takes +12V from PSU using the ATX power plug(the one which burned)
motherboard then does something with that power(or not) using voltage regulator on the motherboard and gives it to GPUs on the PCI-e slot.
And your GPUs took too much power from PCI-e slots - so the weakest link burnt, usually the weakest link is the ATX power connector itself.
Now to anwser your question(replace 7870 with 7850) we need to know exactly how much power 7850/7870 are using from PCIe slot itself and for how much max power your ATX connector is rated and assuming that not only the connector burnt but also motherboard voltage regulator also - how much max power it can give.
That's a lot of questions ; )) That's why ppl usually use powered risers - consuming +12V directly from PSU and not using it from motherboard.
God damn that sounds complicated.
By finger test you mean touch the power connector and feel it if it's running too hot ? Sounds dangerous