Try to update BIOS first
and if it's possible, try other hard drive on the suspected SATA port.
Maybe your backup hard drive wanna tell you something.
Thats what I was thinking , that drive is not that old but , I think it's the connection on the drive itself.
I am still seeing it hesitate on boot up but , still running smooth.
I do have a back up raptor in another machine I can try , then I will try the port thats free , then bios update.
I can't see how the bios would have something to do with it considering I am running rev 14
Core I7 2600K @ 4.6 | Asrock P67 Extreme 4 | 16 gig Corsair | EVGA Superclocked GTX 780 | Samsung 840 Pro SSD | Seasonic X-850 W
Phenom II 940 @ 3.6 | Gigabyte MA78G-DS3HP | 2x2 gig G-Skill dr2 800 | 500 W Seasonic | WD 640 HDD | EVGA GTX 570