Core 2 Extreme
Core 2 Extreme processors[12][13] are enthusiast versions of Core 2 Duo and Core 2 Quad processors, usually with a higher clock frequency and an unlocked clock multiplier, which makes them especially attractive for overclocking. This is similar to earlier Pentium processors labeled as Extreme Edition. Core 2 Extreme processors were released at a much higher price than their regular version, often 9 or more.