HyperTransport - technical definition

A high-speed interconnection architecture between integrated circuits, introduced in 2001. Code named Lightning Data Transport and developed by AMD and others, the HyperTransport I/O Link Specification defines a protocol and electrical interface between the CPU, memory and peripheral devices.

Since its introduction, HyperTransport's maximum aggregate bandwidth of 32-bit links progressed from 12.8 to 41.6 Gbytes/sec. Version 3.0 also added dynamic link splitting under software control. Called "Un-Ganging," it enables a single unidirectional link to be split into two; each at half the original bit width. HyperTransport (HT) was designed to be fully compatible with legacy PCI (running at 33 or 66 MHz) plus PCI Express and PCI-X technologies. For more information, visit the HyperTransport Consortium at www.hypertransport.org.

                         HyperTransport Version
 Feature                 HT 1.x   HT 2.0   HT 3.0

 Year introduced         2001     2004     2006

 Max clock speed         800 MHz  1.4 GHz  2.6 GHz

 Max bandwidth (GB/sec)  12.8     22.4     41.6

 Hot pluggable           No       No       Yes

 Un-Ganging              No       No       Yes