Advanced Micro Devices, Nvidia Corp. and Via Technologies have not yet started development of their own next-generation universal serial bus (USB) controller as they cannot get specifications of the bus from Intel Corp. The latter denies any wrongdoing or intention to affect competitive positions of AMD, Nvidia and others as well as claims that the spec is not finalized.

“The challenge is that Intel is not... giving the specification to anybody that competes with CPUs and chipsets,” a source close to AMD who is familiar with the dispute between chipset developers and Intel is reported to have said by News.com web-site.

While retaining full backward compatibility with USB 1.0 and USB 2.0, devices that feature USB 3.0 will be able to transfer data at up to 10 times higher speed compared to USB 2.0, or at 4.8Gb/s, meaning that a file as large as 600MB could be transferred in just a second in the best case scenario. In addition, the USB 3.0 specification will be optimized for low power and improved protocol efficiency. USB 3.0 ports and cabling will be designed to enable backward compatibility as well as future-proofing for optical capabilities.

In late 2007 the world’s largest x86 chip supplier formed USB 3.0 promoter group, consisting of HP, Intel Corp., Microsoft Corp., NEC Corp., NXP Semiconductors and Texas Instruments. Even though AMD, Nvidia and Via are the world’s largest providers of computer core-logic sets after Intel Corp., they are not a part of USB 3.0 promo group, but are members of USB Implementers Forum.

Sources close to AMD and Nvidia claim that Intel already has working chip with USB 3.0 support, which means that the specification is complete and the chipmaker may handle it to the industry and competitors. In fact, Intel demonstrated USB 3.0 operation at last year’s Intel Developer Forum, though, it has never said that the technology had been finalized by that time.

“Just as with previous generations of USB, Intel is working hard to get the complete spec to the industry with as little delay as possible in order to drive the wide adoption of USB 3.0. Intel only gives it out once it’s finished. It’s not finished. If it was mature enough to release, it would be released. If you have an incomplete spec and give it out to people, these people will build their chipsets and you'll end up with chipsets that are incompatible with devices. That’s what Intel is trying to avoid,” a source at Intel was quoted as saying.

AMD and Nvidia need to have time to design their controllers according to any specification. Therefore, in case Intel does not provide the USB 3.0 spec soon enough, the companies plan to start to design based on their understanding of the final specification. This may cause incompatibility issues, however, both AMD and Nvidia reportedly do not want to lose competitive advantage of their platforms in the form of USB 3.0.

“We are starting development on it right now. A separate specification – though designed to be compatible with the Intel USB 3.0 spec – has the potential to create incompatibilities. This is not good for users. But we have no choice,” a source close to AMD was quoted as saying.