I tried it with some different SATA adapters from different vendors. According to my experiences the boot time depends on the Bridge chip on the SATA adapter. I got significant slower boottimes with adapters using the JM20330 bridge chip, whereas with adpaters using Marvell-88SA8052 bridge chip (StarTECH, Digitus, equip, ...) boottimes were much faster.
Board Life Status
Board startup date: April 23, 2017 12:45:48