Athlon
Athlon® refers to a series of x86 processors designed and manufactured by AMD. The Athlon was the first seventh-generation x86 processor and the first non-Intel processor to be a mainstream performance leader in more than 20 years.
The Athlon made its debut on August 21, 1999. The name "Athlon" was chose by AMD as short for "decathlon", which the company thought was an appropriate name for its high-performance processor. The original Athlon core revision, code-named "K7", was available in speeds of 500-650 MHz at its introduction and was later sold at speeds up to 1000 MHz. The processor was compatible with Intel's Pentium II instruction set and plugged into a motherboard slot similar to, but not compatible with, the Pentium II.
Internally, the Athlon was essentially a reworking of the K6 processor core designed for compatibility with the EV6 bus protocol used on DEC's Alpha 21264 RISC processor. When AMD also dramatically improved the floating-point unit from the K6 and put a large 128K level 1 cache on the chip, the resulting processor was the fastest x86 in the world. Almost without exception, some version of the Athlon held this distinction between August 1999 and January 2002.
The second-generation Athlon, on the "Thunderbird" core, debuted on June 4, 2000. This version of the Athlon shipped in a traditional pin-grid array (PGA) format that plugged into a socket on the motherboard. It was sold at speeds ranging from 800 to 1400 MHz. Most significantly, the level 2 cache, set at 512K on the K7 but running far slower than the processor itself, was cut to 256K. AMD compensated for this by putting the cache on the chip running at full processor speed and gave the Thunderbird a large performance gain over the K7.
AMD introudced the third-generation Athlon on May 14, 2001, code-named "Palomino". This version, the first to include the SSE instuction set from the Intel Pentium III was sold at speeds between 1333 and 1733 MHz. However, the chip, marketed as Athlon XP, was marketed using the controversial "PR rating" system, which compared its performance to an Intel Pentium 4 processor. Because the Athlon XP is more efficient than a Pentium 4, it delivers the same level of performance at a lower clock speed.
The fourth-generation Athlon, the "Thoroughbred" core, was released June 10, 2002 at 1.8 GHz, or 2200+ on the PR rating system. Two new Athlon XP's, the 2400+ running at 1933 MHz and the 2600+ running at 2066 MHz, were announced on August 21. However, the Athlon is no longer 'officially' the fastest x86 in the world, as Intel's Pentium 4 regained that distinction early in 2002 and has held it since, with its current 2.8 GHz processor benchmarking slighly faster than the 2600+. Unfortunately many of the benchmarks which show such numbers are now held by industry insiders to have been deliberately skewed in Intel's favour; for example the BAPCo tests, which were written by Intel's own engineers.
Future versions of the Athlon will be based on the 64-bit x86-64 "Hammer" technology, and are expected to debut in the first half of 2003.
This article (or an earlier version of it) contains material from the "K7" article from FOLDOC, used with permission.