HyperTransport 3.0 almost doubles bandwidth

HyperTransport is a data bus which is used successfully in AMD’s K8-architecture among others and now the HyperTransport Consortium has announced that they have finalized the specifications for the latest HyperTransport standard. HyperTransport 3.0 gets on where 2.0 left us, and does it with almost doubled bandwidth through a significantly increased clock frequency. HT 2.0 utilized a maximum frequency of 1.4GHz whilst the HT 3.0 standard has increased this clock frequency to a full 2.6GHz and thereby pushed the bandwidth to a impressive 41.6GB/s. Besides a maximum bandwidth increase of 86% from HyperTransport 2.0, there’s a bunch of other news in the HT 3.0 specification that could be interesting for developers.

Technical Features and Benefits of HyperTransport 3.0

· AC mode (Optional) – An innovative AC interconnect mode complements HyperTransport’s traditional DC mode, featuring capacitor coupling, AC/DC auto-sensing and auto-configuring capabilities. The feature extends HyperTransport’s maximum signal transmission distance to 1 meter at maximum specified clock speed with no signal transmission or performance degradation. As a result, the HyperTransport standard can now support long-haul signal transmission typical of backplane and chassis-to-chassis applications. During power-up and in total transparency to system software, HyperTransport 3.0 auto-senses the presence of coupling capacitors (AC) and/or direct connections (DC) within the HyperTransport interconnect fabric and automatically configures each portion of it accordingly.

· Hot plugging – HyperTransport technology-enabled devices can be added to or removed from the HyperTransport fabric without disrupting system operations. HyperTransport cards, systems and subsystems can therefore be deployed in backplane and any mission-critical platforms requiring high system availability.

· Un-ganging mode (Optional) – During system power-up and transparently to system software, 1×16 HyperTransport links can optionally be configured as 2×8 virtual links. This gives system architects extended interconnect flexibility and the ability to fully leverage existing HyperTransport components and cores. Un-ganging mode is particularly valuable in multiprocessor and symmetric multiprocessing environments.

· Power Management Mode – HyperTransport 3.0 carries dynamic, auto-sensing, hardwarebased, self-configuring power management capabilities that give end products the intelligence to best optimize the power consumption of each of their HyperTransport components and modules in real-time and transparently to operating system (OS) and application software.

:: Read on about HyperTransport 3.0’s specifications (PDF)