Just two PCIE connectors plugged closest to the RJ45 and it normally runs for six months minimum, I just look 2 days ago the low hashrate. 
Take a look at your screen shot, ASIC Status, one of your boards is dead, you're hashing with 1/2 an S3.
I use all 4 PCIE connections and gather the three conductors of each polarity to 16 gauge copper stranded good for 15 amps. Short a couple of connectors one time, I tried using only two PCIE and those conductors got warm. So, you're moving a lot of current.