"I'm also using the 88 version on an older 13.7 th model, just set it up, I'll let you know how it goes over the next week or so"

I am using 2 HP Server PSUs, 1x750w (running 1 board) and 1x1200w (running 2 boards and controller)
at 706.25 freq for some reason the single 750w PSU keeps resetting itself. I suspect it's because it might be going bad as I've been using it for almost 2 years.

Temperatures were varying from 78-85 -/+ 2 degrees in any direction.

It seems to run stable at 700 flat, running each board 4950ish-5100ish GH/S

I suspect I could get more if I could get the temperature in my garage lower, ambient air temp is around 78 degrees.

I think come winter time I can play around with it more, I will also try using my Bitmain PSU, though I dont get full potential out of it on 110v plug, I don't have a 220v in my garage.

Thanks for the info on the fan speed mod, I will give it a try!