990FX Extreme3 Sata

What part of the BIOS are you referring to about the drives being recognized? In the Storage Configuration screen, Boot screen, or both?

What do you have the SATA Mode set to in the Advanced -> Storage Configuration screen?

The default setting of SATA Mode is IDE, but unless you are using a very old HDD, set the SATA Mode to AHCI.

If you plan on using RAID, set it to RAID. In that case, the optical drive MUST be connected to the SATA3_5 port, which is the single SATA port that stands up vertically from the mother board. Even if you use AHCI mode, I would still connect the optical drive to the SATA3_5 port.

The SATA IDE Combined Mode option is important when using the SATA3_5 port. I would initially try leaving it set to Enabled with the optical drive. If the optical drive is still not recognized, the set SATA IDE Combined Mode to Disabled.

When you set or change any of these options, you must select Save and Exit the BIOS, and then go right back into the BIOS to see the results of the options being applied by the restart.

The main HDD or SSD for the PC should be connected to the SATA3_1 port, which is the top port of the two stacked ports closest to the bottom of the board.

Are your drives standard SATA drives, and did you double check that the data cables are good and that power is getting to the drives?

Have you tried switch to the other ports?