If BIOS doesn't allow OCing, it means you cannot OC. After all, BIOS is above windows.
You should be able to max out or near max out all said games.
Hmm, is the a bad motherboard in any way capable of reducing my gaming performance? Other than it won't allow me to OC?
Is it in any way a vital component that I require a good MOBO to play the high-end games?