[ubuntu] Bios Setting for,"32Bit Transfer Rate"

Hello,

A Biostar bios gives me the option of the enabling or disabling the 32 bit transfer rate under the SATA Configuration section.

Should I infer from this that if I load a 32 bit Ubuntu os that I set it to 32 and that if I load a 64 bit os that I disable it?

Or will the bios automatically detect and adjust to either a 32 or a 64 bit os?

Or are the SATA transfer rate and the bit rate of the operating system independent of each other?

Thank you.