Hmm, not sure if it was just programmed in but not visible or what. I did some searching and found it for an older 955 asus board:

AI CPU Lock Free - This parameter allows you to determine the internal speed of the
CPU. For the P4 550, if “Enabled” is selected, the internal CPU speed will equal fourteen
times the CPU Frequency. If “Disabled” is selected, the internal CPU speed will equal
seventeen times the CPU Frequency. Also found in “Advanced/Jumper Free”.

probably doesn't mean much.

I don't think vdroop can be corrected all too much by a bios update though, so don't get your hopes up necessarily. but this is indeed a p5b dlx bios.