Yes, that is normal, HDDs take a while to start up, even if they are not the OS drive they are waited for to check. Some BIOS's had a time setting of how long to wait for HDDs, but I don't think our board does. In the Boot menu, set the Add on ROM display to Disabled, same for Full Screen Logo.
Did you try using the Fast boot setting? What did you do to get full capacity access to your 3TB HDDs, the 3TB Unlocker utility, or formatting them as GPT?