Wikipedia
HyperTransport (HT), formerly known as Lightning Data Transport (LDT), is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001. The HyperTransport Consortium is in charge of promoting and developing HyperTransport technology.
HyperTransport is best known as the system bus architecture of modern AMD central processing units (CPUs) and the associated Nvidia nForce motherboard chipsets. HyperTransport has also been used by IBM and Apple for the Power Mac G5 machines, as well as a number of modern MIPS systems.
The current specification HTX3.1 remains competitive for 2014 high speed (2666 and 3200 MT/s or about 10.4GB/s and 12.8GB/s) DDR4 RAM and slower terabyte (around 1GB/sec 1 similar to high end PCIe SSDs ULLtraDIMM flash RAM) technology - a wider range of RAM speeds on a common CPU bus than any Intel Front Side Bus. Intel technologies require each speed range of RAM to have its own interface, resulting in a more complex motherboard layout but with fewer bottlenecks. HTX 3.1 at 26GB/s can continue to serve as a unified bus for as many as four DDR4 sticks running at the fastest proposed speeds. Beyond that DDR4 RAM may require two or more HTX 3.1 buses diminishing its value as unified transport.