IBM (Armonk, N.Y.) and Georgia Tech (Atlanta) claimed that they have demonstrated the first silicon-based chip capable of operating at frequencies above 500 GHz by cryogenically "freezing" the circuit to minus 451 degrees Fahrenheit (4.5 Kelvins).

By comparison, 500 GHz is more than 250 times faster than today's cell phones, which typically operate at approximately 2 GHz, according to the organizations.

Still, it's hard to imagine many commercial applications for a chip that is cryogenically frozen to minus 451 degrees Fahrenheit. Another question is whether speed still matters at a time when chip designers are much more focused on power management. 

Read in full @ IBM's 'frozen chip' claims speed record