I'd say what is my 'thumb rule' with almost all asics, below 90C to avoid miner failure and below 80C for longer life time.
okay then at the under clock my gear is great.
I should have ordered these sooner.
6 of them is only 6 x 725 = 4350 watts
at the underclock of freq 344
fans set to 35% running at 2,640 and 3,540 this is bearable.
I can run six of them on a single 30 amp pdu as 24 x 240 = 5760 watts and I will be at 4350 watts
I run mine on 580-590mh for months without a problem so far. Just saying, temps are under 65°C, Fan speed 95% or so, nothing to complain about