For the Psu-s
I have a question. If you have a machine what eats about 700w and you have a 850w Psu, what will you do if somhow we can overclock them and need some margin?
I have a 1500w psu and a lot of big fans to answer this.
But it's only a theory......
A 850W quality PSU will most probably be enough even for some overclocking if possible, granted a Jupiter uses less than 600W DC power.
And you'll have a psu at 100% load.
Personally I don't like it. (It's my fault)
For a KNC Jupiter it could well end up drawing 750 Watts (perhaps a bit more) -- I would recommend a 1000 Watt supply as the minimum.
It would be better with a 1200 Watt capable supply. (Safety margin)
Most engineers like lots of safety margin. In this case the extra cost is cheap insurance.
I would also use a UPS capable of 1000 Watts for 20 minutes (or 1000 - 1200VA if you like) -- with full time AC line filtering as well. Most of the 1000 Watt level UPS units have AC filtering -- but look for it in the spec.
A lot of places have Solar and Wind turbines contributing the grid -- they cut in and out a lot contributing a lot of electrical noise and over voltage and brown outs -- hence the caution about AC filtering. The power grids are not as stable as they were in pre-green energy days.
fwiw...
Edit: I actually tested a Saturn with a 450Watt Corsair. The 12 Volt lines dropped to 11.5V With a Corsair GS 800 the 12V lines measure 12.25 volts -- which is fine.