I'm setting up a brand new pfsense and it works fine. Then I restore the configuration from another working installation and when I try to reboot it freezes soon after mouting the / partition and detecting the CPU. The last line in my screen is:
TSC: P-state invariant
Open the configuration file with a text editor and if you see any of these lines remove it:
Booting proceeds but all messages are send to the serial port instead of your screen.