question about my 1070 rig

Hey all, i recently set up a 6 card 1070 rig and its going pretty good. im getting 29.5mhs/card at around 1000w from the wall. my only concern is that over time (12 + hours) gpu 0 drops in power use and in performance all cards are set to 80TDP but gpu 0 is only using 60/65 I'm worried that the rig will eventually crash if it keeps dropping.
any thoughts, or ideas welcome, thanks