# Performance Rating > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Performance_Rating > Markdown URL: https://mediated.wiki/source/Performance_Rating.md > Source: https://en.wikipedia.org/wiki/Performance_Rating > Source revision: 1336666700 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) This article is about rating computer CPU performance. For performance rating at the workplace, see [performance rating (work measurement)](/source/Performance_rating_(work_measurement)). For chess ratings, see [rating performance (chess)](/source/Rating_performance_(chess)). Figure of merit developed by AMD, Cyrix, IBM Microelectronics and SGS-Thomson AMD 5x86 (X5) CPU The **PR** (**performance rating**, **P-rating**, or **Pentium rating**) system was a [figure of merit](/source/Figure_of_merit) developed by [AMD](/source/AMD), [Cyrix](/source/Cyrix), [IBM Microelectronics](/source/IBM_Microelectronics) and [SGS-Thomson](/source/SGS-Thomson) in the mid-1990s as a method of comparing their [x86](/source/X86) processors to those of rival [Intel](/source/Intel). The idea was to consider [instructions per cycle](/source/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.[1][2] ## Branding The first use of the PR system was in 1995, when AMD used it to assert that their [AMD 5x86](/source/AMD_5x86) processor was as fast as a [Pentium](/source/Pentium_(original)) running at 75 MHz. The designation "P75" was added to the chip to denote this.[3]: 3 Later that year, [Cyrix](/source/Cyrix) also adopted the PR system for its [6x86](/source/6x86)[1] and [6x86MX](/source/6x86MX) line of processors.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] These processors were faster than Pentiums of the same speed in some benchmarks, so Cyrix gave them a Performance Rating faster than their clock speed.[3] Some [AMD K5](/source/AMD_K5) models also use the PR system. AMD initially branded its [AMD K6](/source/AMD_K6) processors with a "PR2" rating but dropped this after consumer confusion.[4] AMD revived the branding for its [Athlon XP](/source/Athlon_XP), which was released in 2001. The efficient Athlon XP chips could perform better than similarly-clocked chips from Intel's competing [Pentium 4](/source/Pentium_4) line-up, which depended on high clock speeds to overcome their low IPC. As a result, AMD believed consumers would be swayed by the [megahertz myth](/source/Megahertz_myth).[5] These chips were rated against the [Athlon Thunderbird](/source/Athlon_Thunderbird) but were popularly compared to the Pentium 4. As a result, the branding became colloquially known as a "Pentium Rating".[3]: 6 *[Maximum PC](/source/Maximum_PC)* criticized this as making it more difficult for power users to differentiate between the various Athlon XP chips. For example, two chips could be given the same "PR" branding but have much different engineering ([cache](/source/CPU_cache) size, [bus](/source/Bus_(computing)) speed, etc), which would affect their performance at different tasks.[6] ## See also - [iCOMP (index)](/source/ICOMP_(index)) ## References 1. ^ [***a***](#cite_ref-:0_1-0) [***b***](#cite_ref-:0_1-1) Metz, Cade (1996-04-09). ["Trends: Cyrix Scores"](https://books.google.com/books?id=K8IS2A_xDLUC&q=%22P-Rating%22&pg=PA31). *[PC Magazine](/source/PC_Magazine)*. Vol. 15, no. 7. [Ziff Davis, Inc.](/source/Ziff_Davis%2C_Inc.) p. 31. 1. **[^](#cite_ref-2)** ["Cyrix Corporate Information -- New P-Rating System for Microprocessors Simplifies Consumer Evaluation of Personal Computers"](http://www.cyrix.com/corpor/press/1996/pratg-pr.htm). 1996-02-05. [Archived](https://web.archive.org/web/19960926233116/http://www.cyrix.com/corpor/press/1996/pratg-pr.htm) from the original on 1996-09-26. Retrieved 2019-12-17. 1. ^ [***a***](#cite_ref-pcgamer_3-0) [***b***](#cite_ref-pcgamer_3-1) [***c***](#cite_ref-pcgamer_3-2) Lilly, Paul (April 14, 2009). ["A Brief History of CPUs: 31 Awesome Years of x86"](https://www.pcgamer.com/a-brief-history-of-cpus-31-awesome-years-of-x86/). *[PC Gamer](/source/PC_Gamer)*. Retrieved 2023-08-18. 1. **[^](#cite_ref-4)** Shimpi, Anand Lal (1997-04-03). ["AMD K6 Review"](https://web.archive.org/web/20100418035710/http://www.anandtech.com/show/42/amd-k6-review). *[AnandTech](/source/AnandTech)*. Archived from [the original](https://www.anandtech.com/show/42/amd-k6-review) on April 18, 2010. Retrieved 2023-08-18. 1. **[^](#cite_ref-5)** McLaughlin, Laurianne (2001-11-02). ["AMD Strikes Back"](https://web.archive.org/web/20120420111758/https://www.pcworld.com/article/65171/amd_strikes_back.html). *[PC World](/source/PC_World)*. Archived from [the original](http://www.pcworld.com/article/65171/amd_strikes_back.html) on 2012-04-20. Retrieved 2012-01-08. 1. **[^](#cite_ref-6)** Smith, Will (2005). ["AMD, the Feisty Upstart"](https://books.google.com/books?id=Cnj_3fFfPdsC&pg=PA48). *Maximum PC Guide to Building a Dream PC*. [Que Publishing](/source/Que_Publishing). p. 48. [ISBN](/source/ISBN_(identifier)) [0-7897-3193-2](https://en.wikipedia.org/wiki/Special:BookSources/0-7897-3193-2). ## External links - [Processor Performance Rating (P-rating) Specification](https://en.wikichip.org/wiki/processor_performance_rating_(p-rating)_specification), February 1996. Uses Winstone 96. - [P-rating](https://en.wikichip.org/wiki/p-rating) on wikichip --- Adapted from the Wikipedia article [Performance Rating](https://en.wikipedia.org/wiki/Performance_Rating) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Performance_Rating?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.