You should only update the BIOS if you are experiencing an issue that the update specifically resolves. If not, do not update.
Agreed! The following is listed for that bios update....
- Improved memory compatibility. - Support PSC B-die DDR3 Memory - Fix that system is not able to boot from legacy DVD ROM when RAID is activated. - Updated CPU microcode.
So, unless you're having one of those issues, best to leave it alone.