Hi,
I strongly agree with MindoverMaster.
Unless you're experiencing problems, or your motherboard is missing a required feature, which a newer BIOS firmware version can provide, then don't bother with flashing your motherboard's BIOS to a newer version.
While for the majority, BIOS upgrades complete without any problems, its also just as easy for the flashing process to go wrong, and for you to end up with a kaput motherboard. I used to perform regular BIOS updates on a Compaq Desktop machine I once owned, and on three separate occasions, the flashing process went wrong and I had to send the motherboard off to Compaq for reflashing!
. A very frustrating and inconvenient situation to be in. What's more, the same problem occurred on a HP notebook I used to own, and I had to send it in for repair. I think I've learnt my lesson now!
But for completeness, you can check which BIOS version you have by going into the BIOS, or by observing the POST screen, where the BIOS version is usually shown on screen (immediately after powering on the system). As for where to download the latest BIOS firmware version, then assuming the motherboard in question is the Asustek M4A79XTD EVO (as shown in your sig.), you can obtain the latest version, along with the AFUDOS BIOS update utility required to perform the BIOS update, at the following webpage:
http://support.asus.com/download –> Type 'M4A79XTD EVO' in the top-left search field then hit enter.
Looking at the list of BIOS updates for this motherboard, there isn't one which introduces finer control of your motherboard's bus speed. Unfortunately, it seems you're stuck with increments of 200.