HyperTransport Bus (HT)

Last Updated: August 18, 2011

Definition - What does HyperTransport Bus (HT) mean?

A HyperTransport (HT) bus is a bus technology developed by AMD Inc. and used in microprocessors as a low-latency, high-speed, point-to-point link specifically designed to increase the communication speed between the components in a computer system, servers, embedded systems, and networking and telecommunications equipment at up to 48 times compared to older or existing transport technology.

HyperTransport is packet-based, and it sends data in a packet that consists of 32-bit words. It also has power management and is compliant with advanced configuration and power interface specifications. It was designed to:

Use low pin counts and low-latency responses
Be transparent to the operating systems and make very little impact on peripheral drivers
Maintain compatibility with legacy PC buses while being extensible to new systems network architecture buses
Provide significantly more bandwidth than technologies at the time of its release

HyperTransport is handled by the HyperTransport Consortium, which includes AMD Inc., Apple Inc., NVIDIA Corp. and CISCO Inc. among many others.

A HyperTransport bus may also be known as a lightning data transport (LDT) bus.

Techopedia explains HyperTransport Bus (HT)

HyperTransport is AMD’s solution for increasing performance. This is accomplished through parallel communication between the memory and other board peripherals. Because the memory and CPU are in constant communication, they require a dedicated bus structure. However, because the other bus has to support all other parts of the board, it has to be fast, and this is what HyperTransport was designed for.

Unlike the frontside bus, HyperTransport uses separate links for the CPU output and input operations, which allows the CPU to send data in parallel. On the traditional bus, input and output operations cannot be done at the same time.

On processors not based on the AMD 64 architecture, the frontside bus is the only external bus that connects the CPU to all other components of the motherboard. On the AMD64 architecture, the CPU has two external buses. The transport bus is used for direct data transport between the memory and the CPU, while the HyperTransport bus is used for communication between the CPU and all other parts of the motherboard chipset. The HyperTransport bus also allows multiple processors to be interconnected, specifically in server systems.