PLL CPU OC: http://www.overclock.net/t/1250625/what-is-cpu-pll-overvoltage
CPU SFR: https://en.wikipedia.org/wiki/Special_function_register
Don't know what CPU ST PLL is, but all these are generally for over clocking. (OC) http://forums.anandtech.com/showthread.php?t=2289246