Quote from: philipma1957 on November 16, 2014, 12:14:29 AM

at planetcrypto what is the watts for that. >>>> if you get 1600gh and I get 1280gh my way has to be a lot safer since the watts are low.

No clue.
When we initially fired them up we were powering them with EVGA 1300's feed with 120V with a Kill-A-Watt monitoring watts.
Stats were ~1250W @ 240, ~1300W @ 260, and ~1400W @ 270.
Don't have a power meter that will measure @ 240V, hence my cluelessness.
Now powered with DPS1600BB's feed 240V which have about the same efficiency as the EVGA's feed 120V.
So the power draw @ a given clock rate will be in the ballpark.
Hence my use of the "~" character indicating approximate.

If any one knows of a cheap power meter that will run @ 240V I'd sure like to know.
Because I'd sure like to have one in my inventory of test equipment

Gross power draw is not the only consideration when considering safety.
Heat is what causes these things to fail (sometimes violently).
Excessive heat is what caused all the units to fail with all the ugly pictures posted in this forum.
More precisely, not being able to dissipate the heat is what caused the failures.
Configured and mounted vertically, as in the pictures I posted, heat is being managed, keeping chip, board, and cap temperatures within tolerable and safe ranges.
What we are doing is finding out what it takes to safely run these things at elevated clock rates on air.

This elevated clock rate testing speaks to the second part of your post which concerns itself with W/GH/s which is used to predict the most cost effective air cooled clock rate to operate at.
Very likely operation with air cooling @ stock (240) or de-clocked rates will be the most cost effective air cooled operating mode.
But one doesn't know unless tested in the real world to develop stats.

We're a business. We bitcoin mine to make a profit. We are not hobbyists. So finding the most profitable mode of operation is our goal.
We may determine with this Prisma analysis that there is more cost effective air cooled H/W.
The next phase of our testing will be these Prisma boards mounted in 2 Phase Open Bath Immersion Cooling Tanks.
But developing an air cooled base line is the first step.

What follows is a snapshot of our RPi controlled Prisma clocked @ 260.
In my feeble mind 2 things jump out at me versus the image you posted of your RPi controlled Prisma.
1) There is a difference of hashing rate ~300 GH/s.
2) There is a difference of operating temperature of ~70C (158F)

Almost 100% sure that the temp indicated by Minera is the temp of the RPi near one of the vertical connectors on the RPi B+.
The RPi that is controlling ours sits in the incoming air stream and is specifically positioned there to give an indication of incoming air temp.
The RPi that's controlling yours is (by it's own internal measurement) operating some place hot enough to boil water.
If the Rpi is that hot, how hot is the Prisma? and the components contained thereon.
While not having a pic of your configuration, Your Prisma may be operating at or near a thermal failure point. Even in a de-clocked operating mode/state.
Just food for thought.

While the bulk of our air cooled hashing power is/are Bitmain products, we have quite a few different hashing units in our environment. Mostly acquired for immersion cooling testing.
None but the Prisma have the board densities suitable/optimum for OBI cooling. Likely due to the requirement of using air as a thermal transfer medium (which is a poor choice at best).
We have high hopes for the Prisma hashing units primarily because they prove challenging/difficult to cool on air.

IMHO, the Prisma was specifically designed for a Data Center environment with all that brings to the table (Chilled water, adequate air flow, stable abundant power, dislocation from combustible materials, fire suppresion, etc. . .) and not for the home hobbyist that likely will operate these in a bedroom or garage.

But you know what they say about opinions, "Opinions are like assholes, everybody's got one and they all stink."
Maybe I'm just the stinkiest around.

In the previous tirade, I'm not trying to belittle, deride, or criticize your config, just trying to offer some observations/solutions that possibly might prevent a catastrophe.

Best of luck.