I don't own one of the new boards but on the early X99 boards with the new bios for Broadwell CPU's the boot time seems to be longer than on earlier bios for Haswell CPU's, maybe it adds extra time to determine which CPU plus the RAM tests that occur but it is not a board defect that I know of
if you have Windows 10 installed in UEFI mode go to CSM and set disabled may help boot speeds, if you use Win 7 leave enabled or auto
Boot device control set to UEFI only, boot from network devices to disabled, boot to storage device disabled or UEFI first, same for PCIE/PCI device
Secure boot menu, OS type UEFI for Win 10, other for Win 7
These settings may or may not help with boot speeds, and the more memory obviously may extend boot time somewhat
Personally I think people are to concerned with boot speed rather than how your system operates once booted, ASUS puts a lot of effort into making sure there boards operate stable, there is so many combinations of hardware that making sure it is stable with all combinations is extremely difficult