The Pentium Pro was very expensive at launch time and only intended to be used on server and high-end workstation. All the P6 line began on November, 1995 with the Pentium Pro. This engineering sample comes with 512 KB of L2 cache and a clock speed of 166 MHz (66.6 * 2.5 MHz). The core stepping used in this sample is sA1 and the CPUID is 0x617.