some times even other gpu..i change risers as well..pcie slots as well..with 5 gpu working well one day or sometimes few hours,and just crash to 0 mhs..i was thinking its problem with gpu..but i did some benchmarks..gpu work fine..games as well..really strange..right now rig works with 4 gpu without any problem.
use 4 on this on and get a second mobo.
part of the game is taking what they give you so to speak.
the money is in cards not mobos.