Quote from: dunand on April 03, 2015, 03:26:24 PM

Quote from: soy on April 03, 2015, 02:32:31 PM

Quote from: dunand on April 03, 2015, 02:28:43 AM

I tested underclocking-volting the C1.

The best setting was suggested by another user 2 weeks ago:

675/200 530W 803Mhs 0.66W/Mhs
760/250 790W 1008Mhs 0.783W/Mhs

FYI I have an EVGA 1300W gold.

Wish he had included F° & inHg. And is the supply on 120vac or 230vac?

120vac recorded at the wall with a kill-a-watt. It's 21-22C around the miner 32C in the miner web admin. It was 36C with the default setting.

Just did this yesterday, kill-a-watt, 118vac, ambient 79.95°F, 29.52inHg, 250M/0760, 1002.88GH/s(avg) 819watts, 1.233GH/s/w .811w/GH/s.

Then at ambient 77.9°F, 29.54inHg, 243.75M/0675, 982.76GH/s(avg) 792watts, 1.241GH/s/w .8059 w/GH/s.

I'd decided to run my C1's at 243.75M/0675 to reduce the current away from max on that circuit. After I characterize my S3+'s I'll come back and look at 200M/0675 because that frequency agrees with best I found on an S3 but happened to be at the coolest point in the day.

I'd appreciate your feedback when you get to 80°F ambient. I know these are less efficient power supplies and my initial application was at ½ full load capacity but with the C1's they at 56.9% of full capacity each.

Running at 243.75M/0675 @ 79.9°F my hashboards read 35,38,36,38 & 981.12GH/s(avg).

~700 feet above sea level

soy

I had wondered once about an air mass flow sensor and if it would applicable here. But, the LM75A could generate data that would simulate an air mass flow sensor output. So, air flow ability to cool ASICs should determine fan speed. If fan speed is increased according to a formula calculated at sea level it would be less than optimal on a humid day or at higher altitudes. If the fan speed is determined by the LM75A state and increased to lower the LM75A output, then the air's mass is less a factor. I wonder which it is.