What exactly is "Load Optimal Settings" command? Is it for a better performance ? And in adittion: after entering the setup, under CPU my setting is 100/100 MHz. I do have the option to change that to 100/133 or 133/133 MHz. These options shows the potential of my PC to support that or it's a setting that I can apply right now and improve my performance? Thx to everyone for you time....!!!!

It is a good place to start. Optimal factors into account possible downside variables versus some net resultant overall gain being more favorable under specified conditions. That may not be best for your exact usage rather what the author suggested. The exact specs on your processor and motherboard must be understood by you AND technically possible in order to make that choice.