Thoroughbred 'A' is the first 130nm Athlon CPU. Basically it's a die-shrink from the Athlon 'Palomino' which was used in the first Athlon Mobile 4 and Athlon XP processors.

The die-shrink had several advantages: lower power consumption (and thus a cooler CPU), lower production costs because of the smaller footprint and better scalability. Unfortunately the scalability was a bit dissapointing because the Thoroughbred 'A' didn't really clock well beyond 2000MHz. AMD had been struggling getter the aging 180nm Palomino faster than 1733MHz (XP2100+) and the new 130nm Thoroughbred 'A' as only good for the introduction of the XP2200+ which ran at 1800MHz.

In Q4 of 2002 the improved version, namely Thoroughbred 'B', was available which enabled AMD to release the Athlon XP 2600+ in late August.