I think someone told me that the b75ma isn't overclockable with the i5 3570k is that true?
Yep, only z77 boards are able to overclock Ivy Bridge CPUs
The Intel B75 chipset does not allow you to overclock the processor except IGD and is not a BIOS limitation but hardware limitation. If you wish to overclock a processor then you will need to purchase boards with Z77 chipset. Please note this limitation applies to all brands.