Two new chipsets for consumer PCs will be the centrepiece of one of Intel's most significant product launches of the year, this weekend.

It will introduce six new desktop processors alongside the 915 and 925 chipsets, formerly known as Grantsdale and Alderwood, at launch events in New York and San Francisco today. PCs with the new chips will be on sale at retail stores on Saturday, while Intel is expected to make the formal announcement at the start of next week.

Intel tends to refresh its desktop chipset technology about once a year to add new features or technologies. The 915 and 925 chipsets add various new technologies to consumer desktop PCs, including the PCI Express interconnect technology and support for DDR2 memory. Intel has also improved the integrated graphics chip that ships with certain versions of the new chipsets, as well as the audio technology within the platform.

Three chipset models will be available from PC vendors. The 915G includes the integrated graphics chip, while the 915P is designed for use with graphics cards from companies like Nvidia and ATI. The 925X is a high-performance chipset for advanced users.

PCI Express allows data to travel at faster rates throughout the chipset than permitted by the current PCI standard. It will help improve overall system performance and pave the way for future expansion cards such as HDTV (high-definition television) tuners or advanced graphics technology, according to Intel.

It works by changing the basic architecture of the bus from a parallel design to a serial one, said Gordon Haff, an analyst with Illuminata. This allows signals to move at faster rates throughout the chipset, he said.

DDR2 memory is an update to current mainstream memory technology. It allows memory chips to run faster than the current 400MHz standard by improving signal quality and increasing the number of signals that can be processed by a memory chip. PCs with the new chipsets will be available at launch with DDR2 chips at 400MHz and 533MHz, but analysts don't expect the technology to become a mainstream product until later this year or early next year.

The new chipsets will allow users to include integrated wireless access point technology, but that capability will trickle out of Intel this year and will not be available at launch, said Dan Snyder, an Intel spokesman. The wireless technology is connected to the chipset through a PCI card, which is not ready for commercial launch, he said. Systems with wireless access point technology will be available in limited quantities starting later this year.

That delay is another setback for Intel's wireless division. The company was forced to use wireless silicon from a third-party vendor at its Centrino mobile technology launch in March of 2003 after its own products were not ready in time. Intel eventually launched its own Intel-branded wireless chips later in 2003.

Intel envisions the 915 and 925 chipsets as the building blocks for a new generation of entertainment and consumer multimedia PCs. The new products bring advanced DirectX 9.0 graphics to mainstream PCs with Intel's new integrated graphics chip, allowing more users to get what is usually only available through more expensive graphics cards.

PC audio technology is also overhauled for the first time in several years with Intel High Definition Audio, which improves audio quality and supports a wider range of microphone technology, Snyder said.

Along with the new chipsets, Intel will launch a new Pentium 4 Extreme Edition processor at 3.4GHz and five new Prescott Pentium 4 processors that use a new packaging technology called LGA775 (land grid array packaging with 775 pins). The new packaging technology allows Intel to get more power into the new chips and improves the quality of the electrical signals traveling to the chip.

The new Prescott Pentium 4 processors use Intel's new processor numbering system. The fastest chip is the Pentium 4 560 processor at 3.6GHz, followed by the 550 processor at 3.4GHz, the 540 processor at 3.2GHz, the 530 processor at 3GHz, and the 520 processor at 2.8GHz.