HyperTransport HTX3 Specification

The HyperTransport[tm] Technology Consortium has released the new HTX3[tm] specification, which is a major enhancement to its HTX[tm] expansion connector specification. The HTX Connector specification defines the electrical and mechanical characteristics of an EATX motherboard interface connector, enabling CPUs to connect directly via a HyperTransport link to add-in card subsystems requiring HyperTransport’s state-of-the-art low latency and bandwidth. The EATX motherboard is a popular architecture used in high-performance workstations, servers, embedded systems and storage systems.

With a rising number of HyperTransport-based field-programmable gate array (FPGA) solutions under its belt and with FPGAs representing the majority of controllers and processors utilized in HTX subsystem products, the HTX3 specification includes a section dedicated to detailed FPGA design considerations and guidelines.

New HTX3 solutions will benefit from the increased performance, flexibility and power management capabilities enabled by the new specification. In addition, backward compatibility preserves the value of existing HTX solutions. HTX3 supports up to 5.2 gigatransfers per second bandwidth (2.6 GHz clock rate), which more than triples the 1.6 gigatransfers per second bandwidth of the previous HTX specification (800 MHz). Moreover, support for link splitting enables designers to implement either one x16 link, one x8 link or two x8 links on a single connector. The ability to split one HyperTransport link into two allows the HTX subsystem to be connected to separate CPUs for better clustering performance and RAS support, a capability that is increasingly required by high-performance subsystems operating in multiprocessor designs.

HTX3 also includes support for more sophisticated power management. Users can now leverage a signal pair to enable and disable link activity during power management state transitions. The specification also offers dynamic, auto-sensing, hardware-based, self-configuring power management capabilities that give end products the intelligence to best optimize the power consumption of HyperTransport components. As a result, the HTX3 specification enables designers to take full advantage of a broad range of power management states for maximum energy savings.

More info: HyperTransport Technology Consortium