ATHLON

The Thunderbird was AMD's most successful part since the 386DX-40 ten years earlier. Mainboard designs had improved considerably by this time, and the initial trickle of Athlon mainboard makers has swollen to include every major manufacturer. Their big new fab in Dresden came on-line, allowing further production increases, and the process technology was improved by a switch to copper interconnects. In October 2000 the Athlon "C" was introduced, raising mainboard speed to 266MHz and providing roughly 10% extra performance over the "A" model Thunderbird.

 
 
Athlon XP 2100 Thoroughbred
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In performance terms, the Thunderbird had easily eclipsed the rival Pentium III, and the early Pentium 4s were a long way off the pace, but gradually clawed their way closer. The 1.7GHz P4 (April 2001) served notice that the Thunderbird could not count on retaining performance leadership forever, but thermal and electricity-consumption issues with the Thunderbird design meant that it wasn't practical to take it past 1400MHz.

AMD released the third major Athlon version on May 14, 2001, code-named "Palomino". This version, the first to include the SSE instuction set from the Intel Pentium III as well as AMD's 3DNow, was introduced at speeds between 1333 and 1733 MHz. The major changes were optimisations to the core design to increase efficiency by roughly 10% over a Thunderbird at the same clockspeed, and power consumption reductions to allow it to be clocked faster.

The Athlon XP was marketed using a PR rating system, which compared its performance to an Athlon Thunderbird. Because the Athlon XP has much higher IPC (instructions per clock) than the Pentium 4 (and about 10% higher than a Thunderbird), it is more efficient and delivers the same level of performance at a lower clock-speed, or higher performance at the same 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. 2700+ and 2800+ Thoroughbred-core parts were also announced, but became available in insiginificantly small quantities.

Fifth-generation Athlon Barton-core parts released in early 2003 featured PR ratings of 2500+, 2600+, 2800+ and 3000+. While not faster than Thoroughbred-core processors in megahertz terms, they earned their higher PR-rating-per-megaherz from featuring additional full-speed on-chip cache RAM. The Thorton core is a variant of the Barton with half the cache disabled.

Some AMD proponents claim that these new parts regained performance leadership for the Athlon, but this remained in doubt. Much controversy surrounds the benchmarks which are used to measure performance leadership. In particular, industry insiders point out that some test have been deliberately skewed in Intel's favour - notably the BAPCo tests, which were written by Intel's own engineers.

Most observers considered that the Athlon was no longer the fastest x86 in the world, believing that that Intel's Pentium 4 overtook the Athlon XP early in 2002 and held its until February 2003, with the 3.06 GHz P4 benchmarking slighly faster than the Athlon 2700+. At the time, the question was moot: AMD had yet to deliver the 2700+ and 2800+ in commercial quanties; they did not begin to ship in volume until well into the first quarter of 2003. However, as the initially troublesome transition to the 0.13 micron process neared completion, AMD began producing large numbers of 0.13 micron parts in the 1700 to 2400 speed grades (usually a sign that faster grades are not far away) and, in mid February 2003, announced the Athlon XP 3000+ to ship in volume in early March of 2003. Pending an Intel reply, the 3000+ has according to AMD reclaimed the "fastest X86 in the world" title for the Athlon once again. However reviewers' opinions on this are split, with most believing the top Intel part to still be faster.

The latest model, Athlon XP 3200+, works with a faster 400MHz (200MHz DDR) front side bus and beats Pentium 4 in many applications.

see also: List of AMD microprocessors

This article contains some material from the "K7" article from FOLDOC, used with permission.