Hi sp_ how do you get such a low power usage per rig?, amazing!, and you use windows so that includes 8W of the hard drive, are you including the percentage of the computer power consumption as well?  (cards + computer W /amount of cards?)
are you measuring at the wall?, are you taking into consideration active/reactive power (I say W because it's easier but i actually measure VA) (I mean, are you measuring using a true-RMS power meter?) I use a APPA A18plus clamp meter.

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windows is totally out of the question, stability issues, freezes, weird problems at startup, cards dropping without reason every now and then, i tried that a couple of years ago with the AMD farm and drive me crazy!, it wasn't a day that I didn't have 1 rig with problems, with linux, i can mine for months without a single hiccup, also manage them is a lot easier, and I can run everything from a flash drive, I don't even care about powering them off, just cut off the power, i know that flash storage+linux works 100% all the time!, also it's way easier to clone every miner.

If I use windows, 30% of the time it will launch the startup repair and I will need to plug in a monitor and KBD to say NO, geez!. (and here power outages are very frecuent, so i need to be sure that rigs will power on automagically every single time when I'm not there.
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also, mining, kills hard drives like crazy, unless use SSD which are expensive here.

Someone mention that I should use GOLD PSUs, i will love it but price of GOLD psu here are impossible, not to mention that are very difficult to find, specially the small (500W 600W) ones.

example:
a 1000W sentey bronce PSU costs here 370 dollars
a 1000W sentey platinum PSU costs here 620 dollars

that's mad!, almost twice the price!.

I will try your latest version as soon as I have a working version with cuda 7.5 and last driver
tomorrow I will look for the platium PSU and test it to see the difference, I only bought one because of the price.
will post results, thank you for the data!.