First. Ask yourself why you want to do it. I've said many times before, there are countless people that have got it wrong here, and lived to regret trying.
Second. Unless you have specific error messages saying you need to update the BIOS, or you are suffering from constant crashes, it is doubtful that an update will affect the speed - if that's what your after.
So, what are you trying to achieve and what speed is your CPU?