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Old 2008-05-11, 01:46   #3
Prime95
P90 years forever!
 
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Aug 2002
Yeehaw, FL

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// In Primenet v4 we used a 90 MHz Pentium CPU as the benchmark machine
// for calculating CPU credit. The official unit of measure became the
// P-90 CPU year. In 2007, not many people own a plain Pentium CPU, so we
// adopted a new benchmark machine - a single core of a 2.4 GHz Core 2 Duo.
// Our official unit of measure became the C2GHD (Core 2 GHz Day). That is,
// the amount of work produced by the single core of a hypothetical
// 1 GHz Core 2 Duo machine. A 2.4 GHz should be able to produce 4.8 C2GHD
// per day.
//
// To compare P-90 CPU years to C2GHDs, we need to factor in both the
// the raw speed improvements of modern chips and the architectural
// improvements of modern chips. Examining prime95 version 24.14 benchmarks
// for 640K to 2048K FFTs from a P100, PII-400, P4-2000, and a C2D-2400
// and compensating for speed differences, we get the following architectural
// multipliers:
//
// One core of a C2D = 1.68 P4.
// A P4 = 3.44 PIIs
// A PII = 1.12 Pentium
//
// Thus, a P-90 CPU year = 365 days * 1 C2GHD *
// (90MHz / 1000MHz) / 1.68 / 3.44 / 1.12
// = 5.075 C2GHDs
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