The P rating or performance rating or Pentium - rating is a "unit" with which the speed of a processor with an appropriately clocked Pentium processor ( Pxx ) is compared. For the comparison of 'normal' office applications were used. The floating point performance was generally much lower.
The rating was first introduced by AMD at Am5x86, and later of the Cyrix 5x86 Cyrix and NexGen ( NexGen Nx586 ) used to better afford the competition at that time Pentium can. Cyrix was with the MII (later 6x86MX ) the last manufacturer of this comparison used.
By using different architectures and bus speeds as well as the Intel processors were compared with each other not only on the clock rate. Therefore, Intel developed the iCOMP index based on a set of benchmark applications (including CPUmark32, Norton SI -32, SPECint_base95, SPECfp_base95 ). Since this also very much based on floating point, where Intel has been a leader in x86 CPUs, so that the projection should be documented.
With the NetBurst architecture of the Pentium 4 and Intel moved their high cycle numbers turn to clock frequency as a unit. To remain comparable established AMD with the AMD Athlon XP later again a similar QuantiSpeed above mentioned name which is based on clock speed of the Pentium 4.
A 486 ( a Am5x86 - P75 ) runs at 133 MHz and is about as fast as a Pentium processor running at 75 MHz. So the 486 has a Pentium rating of 75 The rating is here in the name (...- P75 ).
An AMD Athlon processor with a rating of " 2000 " should therefore be equally fast or faster than a Pentium 4 processor running at 2000 MHz. Officially, the P rating, however, is not intended to compete with the clock rates of P4 from the house of the competitors, but the comparison with the Athlon Thunderbird series from the house.
- Computer Architecture