Problem related to bios setup

Question

I have by mistaken disabled 32bit mode in bios setup in the hard disk configuration in "Windows Vista Home Basic" but the computer was normally started . I want to know that whether the 32 bit mode should be enabled or disabled in the boot up menu so that performance of computer is not affected????Now what should i do, I should enable or disable 32 bit mode in the boot up menu in "Windows Vista Home Basic"????