Did I read correctly that it only needs 2 PCI-e cables connected to run as normal (not overclocked)?
Correct. 2 for regular, 4 for OC'ing.
What I do not understand is this sentence: "Dont parallel connected different DC input from different PSU into the same Hashing board." So does this mean you need two PSU if you're overclocking?
I understand they mean dont use 2 PSU for same hashing board. Anyways, with 1 PSU u can connect 4 PCI-e so no problem
yeah this is most likely exactly what they mean.
but with 2 psu's each one doing one board each even thou it seems okay I will let some one else do it first.
Depending on how the shipping goes I might be the guinea pig here. My understanding is that the reason, the only reason, to use two PSU's is to overclock. If you are not planning to OC one PSU is all that you should need. In my case my PSU army is a mix of Corsair 750's and Thermaltake 850's so if I want to OC I am going to have to use the dual config.