Processor Performance Rating (PR or P-Rating), often mistaken for "Pentium Rating", was a rating system that allowed various x86 manufacturers to gauge the performance level of their microprocessors against equivalent Pentium-level performance. PR specifications were finalized on January 25 and were introduced on February 5, 1996 in a collaborated effort by AMD, IBM, SGS-Thomson, and Cyrix to provide a way to report processor performance.

With the introduction of K6 in 1997, AMD extended this rating system by introducing PR2, comparing models against Intel's Pentium II models. However, the rating system was quickly dropped when K6 processors exceeded PII performance clock-for-clock. The system was later revived for Athlon XP for comparison with Pentium 4.

Measuring P-Rating

Performance rating was obtained by:

1. Obtain a representative target system that supports both the Pentium and Cyrix/IBM/AMD processor (e.g. Am5x86 / K5).
2. Run Winstone 96 using the Pentium Processor and record the scores for the various frequencies.
3. Defragment the hard disk after each test run
4. Replace the Pentium processor with target processor (e.g. Am5x86).
5. Run Winstone 96 using the target processor and record the score for this processor.
6. Compare the Winstone 96 score you get against the Pentium processors. The target processor's P-Rating is based on the highest freqeucny of the Pentium processor that the target processor's Winstone score surpasses.

Documents

• /IBM Microelectronics: Four companies announce new, simplified method for consumers to measure microprocessor performance in PCs
• /Processor Performance Rating (P-rating) Specification
• AMD-K5 Processor Performance Brief; Publication #20084 Revision B/0; June, 1996.

Software

• Ziff-Davis PC Benchmarks CD-ROM (PC Magazine Labs); Ziff-Davis Publishing Group PC Benchmarks CD-ROM, including Winstone 96 and Winbench 96 benchmarks. From PC Magazine Labs, including CPUmark32 and full-motion video tests. October, 1995.

Models With PR

Processors With P-Rating
Model	Family	Launched	P-Rating	Frequency	Bus
AM486DX5-133V16BGC	Am5x86	1997	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AM486DX5-133V16BHC	Am5x86	1997	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AM486DX5-133W16BGC	Am5x86	1997	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AM486DX5-133W16BHC	Am5x86	1997	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-K5-PR100ABQ	K5	17 June 1996	P100	99.99 MHz 0.1 GHz 99,990 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR100ABR	K5	17 June 1996	P100	99.99 MHz 0.1 GHz 99,990 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR120ABQ	K5	7 October 1996	P120	90 MHz 0.09 GHz 90,000 kHz	60 MHz 0.06 GHz 60,000 kHz
AMD-K5-PR120ABR	K5	7 October 1996	P120	90 MHz 0.09 GHz 90,000 kHz	60 MHz 0.06 GHz 60,000 kHz
AMD-K5-PR133ABQ	K5	7 October 1996	P133	99.99 MHz 0.1 GHz 99,990 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR133ABR	K5	7 October 1996	P133	99.99 MHz 0.1 GHz 99,990 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR150ABR	K5	6 January 1997	P150	105 MHz 0.105 GHz 105,000 kHz	60 MHz 0.06 GHz 60,000 kHz
AMD-K5-PR166ABQ	K5	6 January 1997	P166	116.66 MHz 0.117 GHz 116,660 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR166ABR	K5	6 January 1997	P166	116.66 MHz 0.117 GHz 116,660 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR166ABX	K5	6 January 1997	P166	116.66 MHz 0.117 GHz 116,660 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR200ABX	K5	April 1997	P200	133.33 MHz 0.133 GHz 133,330 kHz	66.66 MHz 0.0667 GHz 66,660 kHz
AMD-K5-PR75ABR	K5	7 October 1996	P75	75 MHz 0.075 GHz 75,000 kHz	50 MHz 0.05 GHz 50,000 kHz
AMD-K5-PR90ABQ	K5	7 October 1996	P90	90 MHz 0.09 GHz 90,000 kHz	60 MHz 0.06 GHz 60,000 kHz
AMD-SSA/5-75ABR	K5	27 March 1996	P75	75 MHz 0.075 GHz 75,000 kHz	50 MHz 0.05 GHz 50,000 kHz
AMD-SSA/5-90ABQ	K5	27 March 1996	P90	90 MHz 0.09 GHz 90,000 kHz	60 MHz 0.06 GHz 60,000 kHz
AMD-X5-133ADY	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133ADZ	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133SDW	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133SDY	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133SDZ	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133SFW	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133SFY	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-133SFZ	Am5x86	1996	P75	133 MHz 0.133 GHz 133,000 kHz	33 MHz 0.033 GHz 33,000 kHz
AMD-X5-150ADW	Am5x86	1996	P75+	150 MHz 0.15 GHz 150,000 kHz	50 MHz 0.05 GHz 50,000 kHz
AMD-X5-150ADY	Am5x86	1996	P75+	150 MHz 0.15 GHz 150,000 kHz	50 MHz 0.05 GHz 50,000 kHz
AMD-X5-150ADZ	Am5x86	1996	P75+	150 MHz 0.15 GHz 150,000 kHz	50 MHz 0.05 GHz 50,000 kHz
AMD-X5-160	Am5x86		P75+	160 MHz 0.16 GHz 160,000 kHz	40 MHz 0.04 GHz 40,000 kHz
Count: 31