AMD acknowledges Sempron processors are based on Athlon XP

"There is overlap between the two product lines," said Bahr Mahony, a mobile marketing manager with AMD, who conceded that in some cases the Sempron processors could be the same die as Athlon XPs, with different clock frequencies specified.

The Athlon XP family was originally launched in October 2001.

The Sempron series uses at least three different die, with some based on the Thoroughbred processing core, others on the Barton core while the high-end desktop Sempron is based on the Dublin core. The desktop version also uses the hypertransport bus to memory rather than a front-side-bus, Mahony said.

Sempron processors are made using a 0.13-micron manufacturing processes. So-called "Mobile Sempron" processors are based on the Dublin core, which only surfaced in one Athlon XP processor, Mahony said.

Asked the difference was between Sempron and previously announced Athlon XP processors, Mahony cited a combination of features such as on-chip cache size along with the pairing of the guaranteed frequency of operation for the main processor and the the front-side bus.

"There we certain FSB frequencies we did not end up shipping in Athlon XP," said Mahony. Athlon XP processors have FSB frequencies of 266 and 333 MHz.

Mahony said different cache sizes could be achieved by changing the way on-chip cache was connected. Or, he added, a chip could be laid out again and a new die created to minimize die area and cost.