In the summer of 2002 AMD began shipping its first desktop processor built using a 0.13-micron fabrication process. AMD expects the transition to the finer process technology – the Thoroughbred core is a minuscule 80mm2 compared to its predecessor’s 128mm2 – to deliver improved performance, lower power and smaller die sizes. The plan is for all of the Athlon processor family to have been moved to the 0.13-micron process technology by the end of 2002.
In fact, since the new core is unchanged architecturally, it’s no faster than the previous Palomino core at the same clock speed. However, it requires only 1.65 volts compared to its predecessor’s 1.75 volts and the die-shrink has given AMD a clear advantage over rival Intel in this respect, the Pentium 4 having a much larger die size (128mm2 ), and therefore being more expensive to manufacture.
That said, the Thoroughbred was a disappointment to many in the industry who were doubtful that it provided AMD with much scope for increased clock speeds before the company’s Barton core – with twice the amount of L2 cache – was due by year end or early 2003. The announcement, little more than a couple of months later, of Athlon XP 2400+ and 2600+ processors – built on a so-called Thunderbird B core – came as something of a surprise.
On the surface, the new Thoroughbred doesn’t look that much different compared to the original. Its basic specifications remain unchanged, with 128K of Level 1 and 256K of Level 2 on-die cache, 1.65V core voltage, a Socket A interface and an 0.13-micron copper process. The changes have occurred in the areas of physical design and manufacture and the extra performance has been gained as a result of adding an extra metal layer and decoupling capacitors to the core and overhauling the CPU data paths. These gains are at the cost of higher production costs, since greater chip complexity entails more advanced production methodologies.