A new Pentium 4 processor running at 2.4GHz, as yet officially unannounced by maker Intel, has appeared in the component shops of Tokyo's Akihabara district, akin to London's Tottenham Court Road as a centre of over-the-counter technology sales.

The sudden appearance does, however, conform to the industry chip roadmap leaked to PC Advisor last year.

According to Intel's roadmap, high-end P4s running at 2.4GHz are due out in the second quarter of this year, which starts in April.

The Sato Musen store began selling the chips over the weekend but has already sold out of its initial supply, a salesman at the shop said. The shop received a single tray of the chips from an undisclosed source and does not know when further chips will be available, the salesman said. However, he said Intel is expected to officially launch the chip in early April.

Intel last introduced new chips in the P4 line on 7 January this year when it announced the 2.2GHz version of the chip.

That announcement signalled a move to more advanced 0.13-micron architecture for the product line, something which enabled Intel to double the amount of onboard cache memory to 512KB. At the same time, a 0.13-micron version of the existing 2GHz P4 was also introduced.

In Akihabara, the 2.4GHz chips were selling for around £400.

An Intel Japan spokesman declined to offer any details of the new chip. "It is not an officially announced product," said Hiasashi Nagai. "We cannot give you the exact [launch] date but we plan to release it shortly."

"When Intel announces the products officially, many PC makers also announce their PCs at the same time so we actually start shipping to the industry well in advance," he said. "So sometimes we see some products get to the market before the launch date."