Quote from: Optimizer on June 24, 2016, 08:20:22 PM

Quote from: E on June 24, 2016, 07:18:40 PM

I wanted to add some DPS-2000BB efficiency numbers to this thread, as I've recently been measuring DC and AC draw on my S9 at various clock speeds.

Counting 12V cable losses, I'm seeing 88.3 to 88.7% efficiency everywhere from 800W up to 1400W DC. Ignoring cable losses the efficiency is 89.7 to 90%.

This is all at a 208V input voltage... efficiency should be higher with higher input voltage but I haven't been able to test that yet.

Higher input voltage, implies lower input current (Usually). If your losses are dominated by I^2 * R, then it will help.

208V vs 240V efficiency numbers aren't commonly published, but the difference is likely to be less than 0.5% or so.

For example, an unspecified HP PSU measured in 2007:

BTW I'm making my measurements with a calibrated Xitron 2503AH (http://www.xitrontech.com/products/general-purpose-power-analyzers/#2503ah) with an external 500A precision shunt for the DC current; the Xitron is good to better than 0.05% on the internal I/V measurements but the shunt is only spec'd to 0.1% so that dominates the error.

One cool thing you can observe with this is how current draw from a miner increases by 10s of watts as everything warms up to operating temperature. I'll try to get a video of that because it is pretty interesting to watch!