32bit or 64 bit

Solution
Whether the PC is 32 or 64 bit is defined by your OS, not your hardware ( except for some very very old CPUs that don't support 64bit OS ). 32/64 bit are just different types of OS ( generally, 64bit version of OS supports more RAM, and some new programs only run on a 64bit OS, while 32bit ones is more friendly to old programs that haven't received an update for years ). So, without an OS installed, your question is invalid.
Whether the PC is 32 or 64 bit is defined by your OS, not your hardware ( except for some very very old CPUs that don't support 64bit OS ). 32/64 bit are just different types of OS ( generally, 64bit version of OS supports more RAM, and some new programs only run on a 64bit OS, while 32bit ones is more friendly to old programs that haven't received an update for years ). So, without an OS installed, your question is invalid.
 
Solution
It is not depend on motherboard whether it is 32bit or 64bit.
It depends on your OS.
If you have 4GB or less ram and your cpu has 6 or less than 6 cores then you can use 32bit OS.
But if you have More than 4GB ram and an Octacore processor then you'll ultimately need a 64bit OS.
32bit OS is for low-medium end hardware and 64bit OS is for High end hardware.