GA-P55A-UD3 (rev.1) won't boot when ahci mode is selected

[cbbella]

My Configuration:
Motherboard:  Gigabyte GA-P55A-UD3 (rev 1.0, BIOS F11)
RAM:  Crucial Ballistix 1600mhz DDR3,  BL2KIT25664BN1608 4GB kit, 2kits 8GB Total Ram
CPU: Intel i7-870
Video Card: EVGA GeForce GTX 460 SE
HARD DRIVE:  Seagate Pipeline HD2 500GB
2 DVD-RW Optical Drives
PC CASE - Antec Sonata III with 500-Watt power supply


hi, my pc has no operating system installed as yet. the pc boots up and i go into the bios to load optimized settings and then change it from IDE to AHCI mode but then it will only POST so far and gets stuck at 23, see attached photo. i then have to restart with the hd unplugged as it will not let me back into the bios.  once back into the bios i change it back to IDE mode then reconnect the hd and it will boot normal.

my problem is that i need it to boot in AHCIi mode as my OS "OS X Mavericks" requires AHCI to be selected at install. can you offer me a solution please

[dmdilks]

Where are the HD connected too. They should be on the blue ports and not the white. The white ones are for G-sata.

[cbbella]

yes they are connected to the blue ports