The real cool thing about this initiative is that the organisation managed to convince Intel and AMD to standarize certain aspects of the hardware. Yes, they collaborated. The AMD and Intel motherboard will have the same form factor, mounting holes, management interface and so on. The ODM/OEM has to design only one server: the AMD board can be swapped out for the Intel one and vice versa. The Mini-Mezzanine Slot and the way the power supply is connected, it is all standardized.
AnandTech - OpenCompute servers and AMD Open 3.0