Comment by andy_threos_io

Nowadays, it's better to use x86_64 only. The 32 bit x86 has many drawbacks. The 64 bit is much cleaner and better in many many ways.

  -no segmentation, flat address space
  -better interrupt handling
  -better system call
  -more registers
  etc.

Also we found that Qemu or other Virtualization technology may cover up some of the hardware issues. Eg. Beside, that every hardware device (keyboard, usb, display, disk etc.) will have some simplified behavior, if you emulate an ARM cpu on x86_64 host, than the cache coherency will totally messed up on real hardware.