The PR (Performance Rating, P-rating) system was a figure of merit developed by AMD, Cyrix, IBM Microelectronics and SGS-Thomson in the mid-1990s (Cyrix announced it in February 1996) as a method of comparing their x86 processors to those of rival Intel. The idea was to consider instructions per cycle (IPC) in addition to the clock speed, so that the processors become comparable with Intel's Pentium that had a higher clock speed with overall lower IPC.
