From their FAQ: Q: Why preorders? Why can't I evaluate a production machine right now? A: Although we have Talos™ II hardware in our labs, IBM has not yet rel

From their FAQ: Q: Why preorders? Why can't I evaluate a production machine right now? A: Although we have Talos™ II hardware in our labs, IBM has not yet released the POWER9 CPU to the general public. The POWER9 launch is scheduled for Q4 this year; we intend to make Talos™ II available to everyone shortly after POWER9 launch via our pre-order model. This model allows us to manage supply of the Talos™ II systems for Q4 shipment, and we intend to transition to a more standard ordering model once the POWER9 processor has reached general availablility (GA). Orders placed after our pre-order cutoff will not ship until 2018, and you would be missing out on the benefits of early market access to the POWER9 processor, so we strongly recommend that you place your pre-order as quickly as possible!