Disclosure: Spondoolies Tech was very kind to send me an Sp20 as per
their Legendary Review thread.The obligatory background story: first time I read about bitcoins was mid May 2011, it took me a couple of weeks to reach... consensus with my wife that it was a good idea and to start throwing money and time to mine them.
So I bought five ATI 5830s and put them in three second hand cases I had at work, my son was just 4, so I could not leave their cases open.
I called them the three Knights (the Black one and the White ones) set to fight banking cleptocracy.
I had them in my house... it was hot, we were at the end of June, so I had to keep the window open all day long, my wife did not like the idea anymore...
After them I did the "course of honor" of every respected miner: GPUs, FPGAs and the the Avalons, the first ASICs to reach the market... in hindsight I should have bought them with both hands during December-January 2012, when they were around 3 USD/each... anyway, it has been even funnier this way.
The review:I got my Sp20 unit saturday morning.
First of all, you need to know that my nickname and Spondoolies...
mean nearly the same, pocket change my nickname and a (bigger) cash sum theirs.
I need to stress out that mining, in Italy, has never been an easy task because electricity here is not cheap.
I pay around 0.25 USD/cents per kWh with a commercial contract (home ones are even higher), so, apart from a few moments in bitcoin's history, I've always had the need to use the most power efficient units available (or run them abroad).
Where I'm hosting my Sp20 (mom's garage, which is a solution that I see used
more and more by miners here
) I have a lot more space available than where I live and the help of a photovoltaic system, though a small one, which from late spring to early autumn helps me shave some percent off the electricty costs and produce green bitcoins
I've taken a few photos, before powering on the unit:
unboxing
connectors sideAnd yes, those coins are, you guessed it, "spiccioli"
with case's top removed, the control board is in sight
control board, a very neat unit, with two connectors for the hashing blades on the right side
below the control board there is a metal plate that holds the hashing boards in place.
hashing boards with metal plate removed and visible on the left of the image
As I said, power efficient units are a must here in Italy, next photo shows the Sp20 near a couple of its old ancestors: Cairnsmore 1s (with fan) and a couple of Bitfury's H-boards.
Both of them were the most power efficient solutions at their time
as the Sp20 is today.
CM1s ran around 60-65 W/GH, BitFury's boards run around 1.1 - 1.3 W/GH while a downclocked Sp20 is able to run at 0.55-0.57 W/GH 
For my first test I've used a Recom M1600 I had laying around. The M1600 is an 80+ bronze PSU able to output 1600W, it is 85% efficient, so not the best you can find efficiency wise, but it has enough juice to run an Sp20 at full speed without problems.
I've run it with stock configuration since saturday evening.
Running at 1620 GH/s in 23 C enviroment it was using 1190W at the wall on a 220V circuit.Today I've reduced speed a little
using SP-Tech's recommended tweaking, that is reduce voltage alone, I've reduced max voltage down to 0.70 from 0.75 because chips were throttling due to heat. I'm now hashing at:
with chip temperatures all under control
and power should be around 1 kW at the wall, but I have no photo, alas.
I use slush's proxy to handle all of my units, to be able to point them to the pool of my choice without the need to reconfigure each one of them.
What follows is a graph I make from slush's proxy log file, it shows last day of hashing for this instance of the proxy code which receives the hashing of the Sp20 and of three old Bitfury's rigs (bf2,3,4 in the image).
Tomorrow or the day after it I'll switch the PSU for a Corsair V1000, which is a 80 gold+ unit and I'll reduce unit's hashing speed to reach the sweet spot around 750 W at the wall, where the unit should still able to hash at 1350 GH but with much better power efficiency,
as philipma1957 has already found out.
Stay tuned!
spiccioli.
