Yeah i have the same setup.
sorry you wrote in the post above you only had 2 drives.
Before you setup your array can you make sure that you update the firmware on your Samsung drives. you need to make a bootable USB key or Floppy and make sure the drives are plugged in to the SATA ports on your motherboard, it will detect and update any samsung drives that are connected automaticlly so you can plug in all 4 at once if you want.
firmware has been updated on all my samsung drives.
i also tested all my drives before setting up the raid 5 array.