If your system runs well, I wouldn't do it. There's no need unless you're changing cpus or have serious issues. Leave it alone. I've flashed my board bios many times, and most of the time, don't notice any improvement in performance.
Go over the change log/update notes. It's not compulsory, but if you do notice anything major or a useful change that will help you, such as "Improved Memory Stability" (and you'd happen to be quite an overclocker with RAM) then go ahead and do it.
Ok thanks guys al go have a look at the notes now, but your right if it's not broke dnt fix maybe the best rule here since I dnt wanna mess up haha.
I once updated my BIOS and got a blue screen and couldn't boot up my OS for an hour Had to do a CMOS reset to fix it all, and then reconfigure all my OC settings. So yeah, there's always that little risk...