HyperTransport (HT), formerly known as Lightning Data Transport, is a technology for interconnection of computer
processor
Processor may refer to:
Computing Hardware
* Processor (computing)
**Central processing unit (CPU), the hardware within a computer that executes a program
*** Microprocessor, a central processing unit contained on a single integrated circuit (I ...
s. It is a bidirectional
serial/
parallel
Parallel is a geometric term of location which may refer to:
Computing
* Parallel algorithm
* Parallel computing
* Parallel metaheuristic
* Parallel (software), a UNIX utility for running programs in parallel
* Parallel Sysplex, a cluster of ...
high-
bandwidth
Bandwidth commonly refers to:
* Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range
* Bandwidth (computing), the rate of data transfer, bit rate or thr ...
, low-
latency point-to-point link
In telecommunications, a point-to-point connection refers to a communications connection between two communication endpoints or nodes. An example is a telephone call, in which one telephone is connected with one other, and what is said by one c ...
that was introduced on April 2, 2001. The
HyperTransport Consortium {{Short description, Body responsible for regulating and promoting the HyperTransport technology
The HyperTransport Consortium is an industry consortium responsible for specifying and promoting the computer bus technology called HyperTransport.
O ...
is in charge of promoting and developing HyperTransport technology.
HyperTransport is best known as the
system bus
A system bus is a single computer bus that connects the major components of a computer system,
combining the functions of a data bus to carry information, an address bus to determine where it should be sent or read from, and a control bus to dete ...
architecture of
AMD
Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...
central processing unit
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...
s (CPUs) from
Athlon 64
The Athlon 64 is a ninth-generation, AMD64-architecture microprocessor produced by Advanced Micro Devices (AMD), released on September 23, 2003. It is the third processor to bear the name ''Athlon'', and the immediate successor to the Athlon XP. T ...
through
AMD FX
AMD FX was a series of high-end AMD microprocessors for personal computers which debuted in 2011, claimed as AMD's first native 8-core desktop processor. The line was introduced with the Bulldozer microarchitecture at launch (codename Zambezi), ...
and the associated
motherboard
A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...
chipsets. HyperTransport has also been used by
IBM and
Apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...
for the
Power Mac G5
The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and ...
machines, as well as a number of modern
MIPS systems.
The current specification HTX 3.1 remained competitive for 2014 high-speed (2666 and 3200
MT/s or about 10.4 GB/s and 12.8 GB/s)
DDR4
Double Data Rate 4 Synchronous Dynamic Random-Access Memory (DDR4 SDRAM) is a type of synchronous dynamic random-access memory with a high bandwidth (" double data rate") interface.
Released to the market in 2014, it is a variant of dynamic ra ...
RAM and slower (around 1 GB/
similar to high end
Solid-state drive#Standard card form factors, PCIe SSDs ULLtraDIMM
The ULLtraDIMM is a solid state storage device from SanDisk that connects flash storage directly onto the DDR3 memory bus. Unlike traditional PCIe Flash Storage devices, the ULLtraDIMM is plugged directly into an industry standard RDIMM memory b ...
flash RAM) technology—a wider range of RAM speeds on a common CPU bus than any Intel
front-side bus
A front-side bus (FSB) is a computer communication interface (bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between the ...
. 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 26 GB/s can 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.
Overview
Links and rates
HyperTransport comes in four versions—1.x, 2.0, 3.0, and 3.1—which run from 200
MHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
to 3.2 GHz. It is also a DDR or "
double data rate
In computing, a computer bus operating with double data rate (DDR) transfers data on both the rising and falling edges of the clock signal. This is also known as double pumped, dual-pumped, and double transition. The term toggle mode is used i ...
" connection, meaning it sends data on both the rising and falling edges of the
clock signal
In electronics and especially synchronous digital circuits, a clock signal (historically also known as ''logic beat'') oscillates between a high and a low state and is used like a metronome to coordinate actions of digital circuits.
A clock sign ...
. This allows for a maximum data rate of 6400 MT/s when running at 3.2 GHz. The operating frequency is autonegotiated with the motherboard chipset (North Bridge) in current computing.
HyperTransport supports an autonegotiated bit width, ranging from 2 to 32 bits per link; there are two unidirectional links per HyperTransport bus. With the advent of version 3.1, using full
32-bit
In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32-bit units. Compared to smaller bit widths, 32-bit computers can perform large calculation ...
links and utilizing the full HyperTransport 3.1 specification's operating frequency, the theoretical transfer rate is 25.6
GB/s (3.2 GHz × 2 transfers per clock cycle × 32 bits per link) per direction, or 51.2 GB/s aggregated throughput, making it faster than most existing bus standard for PC workstations and servers as well as making it faster than most bus standards for high-performance computing and networking.
Links of various widths can be mixed together in a single system configuration as in one
16-bit
16-bit microcomputers are microcomputers that use 16-bit microprocessors.
A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two mos ...
link to another CPU and one
8-bit
In computer architecture, 8-bit Integer (computer science), integers or other Data (computing), data units are those that are 8 bits wide (1 octet (computing), octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) arc ...
link to a peripheral device, which allows for a wider interconnect between
CPUs
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...
, and a lower bandwidth interconnect to
peripheral
A peripheral or peripheral device is an auxiliary device used to put information into and get information out of a computer. The term ''peripheral device'' refers to all hardware components that are attached to a computer and are controlled by the ...
s as appropriate. It also supports link splitting, where a single 16-bit link can be divided into two 8-bit links. The technology also typically has lower latency than other solutions due to its lower overhead.
Electrically, HyperTransport is similar to
low-voltage differential signaling
Low-voltage differential signaling (LVDS), also known as TIA/EIA-644, is a technical standard that specifies electrical characteristics of a differential, serial signaling standard. LVDS operates at low power and can run at very high speeds ...
(LVDS) operating at 1.2 V. HyperTransport 2.0 added post-cursor transmitter
deemphasis
Typically, prior to some process, such as transmission over cable, or recording to phonograph record or tape, the input frequency range most susceptible to noise is boosted. This is referred to as "pre-emphasis"before the process the signal will u ...
. HyperTransport 3.0 added scrambling and receiver phase alignment as well as optional transmitter precursor deemphasis.
Packet-oriented
HyperTransport is
packet
Packet may refer to:
* A small container or pouch
** Packet (container), a small single use container
** Cigarette packet
** Sugar packet
* Network packet, a formatted unit of data carried by a packet-mode computer network
* Packet radio, a form ...
-based, where each packet consists of a set of
32-bit
In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32-bit units. Compared to smaller bit widths, 32-bit computers can perform large calculation ...
words, regardless of the physical width of the link. The first word in a packet always contains a command field. Many packets contain a 40-bit address. An additional 32-bit control packet is prepended when 64-bit addressing is required. The data payload is sent after the control packet. Transfers are always padded to a multiple of 32 bits, regardless of their actual length.
HyperTransport packets enter the interconnect in segments known as bit times. The number of bit times required depends on the link width. HyperTransport also supports system management messaging, signaling interrupts, issuing probes to adjacent devices or processors,
I/O transactions, and general data transactions. There are two kinds of write commands supported: posted and non-posted. Posted writes do not require a response from the target. This is usually used for high bandwidth devices such as
uniform memory access
Uniform memory access (UMA) is a shared memory architecture used in parallel computers. All the processors in the UMA model share the physical memory uniformly. In an UMA architecture, access time to a memory location is independent of which proces ...
traffic or
direct memory access
Direct memory access (DMA) is a feature of computer systems and allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU).
Without DMA, when the CPU is using programmed input/output, it is t ...
transfers. Non-posted writes require a response from the receiver in the form of a "target done" response. Reads also require a response, containing the read data. HyperTransport supports the PCI consumer/producer ordering model.
Power-managed
HyperTransport also facilitates
power management
Power management is a feature of some electrical appliances, especially copiers, computers, computer CPUs, computer GPUs and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power st ...
as it is compliant with the
Advanced Configuration and Power Interface
Advanced Configuration and Power Interface (ACPI) is an open standard that operating systems can use to discover and configure computer hardware components, to perform power management (e.g. putting unused hardware components to sleep), auto c ...
specification. This means that changes in processor sleep states (C states) can signal changes in device states (D states), e.g. powering off disks when the CPU goes to sleep. HyperTransport 3.0 added further capabilities to allow a centralized power management controller to implement power management policies.
Applications
Front-side bus replacement
The primary use for HyperTransport is to replace the Intel-defined
front-side bus
A front-side bus (FSB) is a computer communication interface (bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between the ...
, which is different for every type of Intel processor. For instance, a
Pentium
Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and Pe ...
cannot be plugged into a
PCI Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common ...
bus directly, but must first go through an adapter to expand the system. The proprietary front-side bus must connect through adapters for the various standard buses, like
AGP or PCI Express. These are typically included in the respective controller functions, namely the ''
northbridge'' and ''
southbridge''.
In contrast, HyperTransport is an open specification, published by a multi-company consortium. A single HyperTransport adapter chip will work with a wide spectrum of HyperTransport enabled microprocessors.
AMD
Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...
used HyperTransport to replace the
front-side bus
A front-side bus (FSB) is a computer communication interface (bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between the ...
in their
Opteron
Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64 or AMD64). It was released on April 22, 2003, with the ''Sledg ...
,
Athlon 64
The Athlon 64 is a ninth-generation, AMD64-architecture microprocessor produced by Advanced Micro Devices (AMD), released on September 23, 2003. It is the third processor to bear the name ''Athlon'', and the immediate successor to the Athlon XP. T ...
,
Athlon II
Athlon II is a family of AMD multi-core 45 nm central processing units, which is aimed at the budget to mid-range market and is a complementary product lineup to the Phenom II.
Features
The Athlon II series is based on the AMD K10 architect ...
,
Sempron 64,
Turion 64
AMD Turion is the brand name AMD applies to its x86-64 low-power consumption (''mobile'') processors codenamed ''K8L''. The Turion 64 and Turion 64 X2/Ultra processors compete with Intel's mobile processors, initially the '' Pentium M'' and the I ...
,
Phenom
Phenom may refer to:
* AMD Phenom, the 64-bit AMD desktop processor line based on the K10 microarchitecture
** Phenom II, a family of AMD's multi-core 45 nm processors using the AMD K10 microarchitecture
* Phenom (electron microscope), a fast elec ...
,
Phenom II
Phenom II is a family of AMD's multi-core 45 nm processors using the AMD K10 microarchitecture, succeeding the original Phenom. Advanced Micro Devices released the Socket AM2+ version of Phenom II in December 2008, while Socket AM3 versions w ...
and
FX families of microprocessors.
Multiprocessor interconnect
Another use for HyperTransport is as an interconnect for
NUMA
Nuclear mitotic apparatus protein 1 is a protein that in humans is encoded by the ''NUMA1'' gene.
Interactions
Nuclear mitotic apparatus protein 1 has been shown to interact with PIM1, Band 4.1, GPSM2
G-protein-signaling modulator 2, also call ...
multiprocessor
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There ar ...
computers. AMD used HyperTransport with a proprietary
cache coherency
In computer architecture, cache coherence is the uniformity of shared resource data that ends up stored in multiple local caches. When clients in a system maintain caches of a common memory resource, problems may arise with incoherent data, whi ...
extension as part of their Direct Connect Architecture in their
Opteron
Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64 or AMD64). It was released on April 22, 2003, with the ''Sledg ...
and
Athlon 64 FX
The Athlon 64 is a ninth-generation, AMD64-architecture microprocessor produced by Advanced Micro Devices (AMD), released on September 23, 2003. It is the third processor to bear the name ''Athlon'', and the immediate successor to the Athlon XP. T ...
(
Dual Socket Direct Connect (DSDC) Architecture) line of processors.
Infinity Fabric
HyperTransport (HT), formerly known as Lightning Data Transport, 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 ...
used with the
EPYC
Epyc is a brand of multi-core x86-64 microprocessors designed and sold by AMD, based on the company's Zen microarchitecture. Introduced in June 2017, they are specifically targeted for the server and embedded system markets. Epyc processors share ...
server CPUs is a superset of HyperTransport. The
HORUS interconnect from
Newisys extends this concept to larger clusters. The Aqua device from 3Leaf Systems virtualizes and interconnects CPUs, memory, and I/O.
Router or switch bus replacement
HyperTransport can also be used as a bus in
routers and
switches
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
. Routers and switches have multiple network interfaces, and must forward data between these ports as fast as possible. For example, a four-port, 1000
Mbit
The megabit is a multiple of the unit bit for digital information. The prefix mega (symbol M) is defined in the International System of Units (SI) as a multiplier of 106 (1 million), and therefore
:1 megabit = = = 1000 kilobits.
The megabit h ...
/s
Ethernet
Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
router needs a maximum 8000 Mbit/s of internal bandwidth (1000 Mbit/s × 4 ports × 2 directions)—HyperTransport greatly exceeds the bandwidth this application requires. However a 4 + 1 port 10 Gb router would require 100 Gbit/s of internal bandwidth. Add to that 802.11ac 8 antennas and the WiGig 60 GHz standard (802.11ad) and HyperTransport becomes more feasible (with anywhere between 20 and 24 lanes used for the needed bandwidth).
Co-processor interconnect
The issue of latency and bandwidth between CPUs and co-processors has usually been the major stumbling block to their practical implementation. Co-processors such as
FPGAs
A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware de ...
have appeared that can access the HyperTransport bus and become integrated on the motherboard. Current generation FPGAs from both main manufacturers (
Altera
Altera Corporation was a manufacturer of programmable logic devices (PLDs) headquartered in San Jose, California. It was founded in 1983 and acquired by Intel in 2015.
The main product lines from Altera were the flagship Stratix series, mid-ran ...
and
Xilinx
Xilinx, Inc. ( ) was an American technology and semiconductor company that primarily supplied programmable logic devices. The company was known for inventing the first commercially viable field-programmable gate array (FPGA) and creating the fi ...
) directly support the HyperTransport interface, and have
IP Cores available. Companies such as XtremeData, Inc. and DRC take these FPGAs (Xilinx in DRC's case) and create a module that allows FPGAs to plug directly into the Opteron socket.
AMD started an initiative named
Torrenza Torrenza was an initiative announced by Advanced Micro Devices (AMD) in 2006 to improve support for the integration of specialized coprocessors in systems based on AMD Opteron microprocessors. Torrenza does not refer to a specific product or specif ...
on September 21, 2006 to further promote the usage of HyperTransport for plug-in cards and
coprocessors
A coprocessor is a computer processor used to supplement the functions of the primary processor (the CPU). Operations performed by the coprocessor may be floating-point arithmetic, graphics, signal processing, string processing, cryptography or ...
. This initiative opened their "Socket F" to plug-in boards such as those from XtremeData and DRC.
Add-on card connector (HTX and HTX3)
![HyperTransport16 pcie8riser pcie16](https://upload.wikimedia.org/wikipedia/commons/1/1e/HyperTransport16_pcie8riser_pcie16.jpg)
A connector specification that allows a slot-based peripheral to have direct connection to a microprocessor using a HyperTransport interface was released by the HyperTransport Consortium. It is known as HyperTransport eXpansion (HTX). Using a reversed instance of the same mechanical connector as a 16-lane
PCI Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common ...
slot (plus an x1 connector for power pins), HTX allows development of plug-in cards that support direct access to a CPU and
DMA to the system
RAM
Ram, ram, or RAM may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
* ...
. The initial card for this slot was the
QLogic InfiniPath InfiniBand HCA. IBM and
HP, among others, have released HTX compliant systems.
The original HTX standard is limited to 16bits and 800MHz.
In August 2008, the HyperTransport Consortium released HTX3, which extends the clock rate of HTX to 2.6 GHz (5.2 GT/s, 10.7 GTi, 5.2 real GHz data rate, 3 MT/s edit rate) and retains backwards compatibility.
Testing
The "DUT" test connector is defined to enable standardized functional test system interconnection.
Implementations
*
AMD
Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...
AMD64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mod ...
and Direct Connect Architecture based
CPUs
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...
*
AMD
Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...
chipsets
** AMD-8000 series
**
AMD 480 series
**
AMD 580 series
**
AMD 690 series
**
AMD 700 series
**
AMD 800 series
**
AMD 900 series
*
ATI
Ati or ATI may refer to:
* Ati people, a Negrito ethnic group in the Philippines
**Ati language (Philippines), the language spoken by this people group
** Ati-Atihan festival, an annual celebration held in the Philippines
*Ati language (China), a ...
chipsets
** ATI
Radeon Xpress 200 for AMD processor
** ATI
Radeon Xpress 3200 for AMD processor
*
Broadcom
Broadcom Inc. is an American designer, developer, manufacturer and global supplier of a wide range of semiconductor and infrastructure software products. Broadcom's product offerings serve the data center, networking, software, broadband, wirel ...
(then
ServerWorks
ServerWorks Corporation was an American fabless semiconductor company based in Santa Clara, California, that manufactured chipsets for server computers and workstations running IA-32 microprocessors. Founded as Reliance Computer Corporation in ...
) HyperTransport SystemI/O controllers
** HT-2000
** HT-2100
*
Cisco
Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, ...
QuantumFlow Processors
* ht_tunnel from
OpenCores
OpenCores is a community developing digital open-source hardware through electronic design automation (EDA), with a similar ethos as the free software movement. OpenCores hopes to eliminate redundant design work and slash development costs. A ...
project (MPL licence)
*
IBM CPC925 and CPC945 (
PowerPC 970 northbridges) chipsets
*
Loongson
Loongson () is the name of a family of general-purpose, MIPS architecture-compatible microprocessors, as well as the name of the Chinese fabless company (Loongson Technology) that develops them. The processors are alternately called Godson pro ...
-3
MIPS processor
*
Nvidia
Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...
nForce chipsets
** nForce Professional MCPs (Media and Communication Processor)
**
nForce 3 series
**
nForce 4
The nForce4 is a motherboard chipset released by Nvidia in October 2004. The chipset supports AMD 64-bit processors (Socket 939, Socket AM2 and Socket 754) and Intel Pentium 4 LGA 775 processors.
Models nForce4/nForce4-4x
nForce4 is the secon ...
series
**
nForce 500 series
**
nForce 600 series
**
nForce 700 series
**
nForce 900 series
*
PMC-Sierra
PMC-Sierra was a global fabless semiconductor company with offices worldwide that developed and sold semiconductor devices into the storage, communications, optical networking, printing, and embedded computing marketplaces.
On January 15, 2016, ...
RM9000X2
MIPS CPU
*
Power Mac G5
The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and ...
*
Raza Thread Processors
* SiByte
MIPS CPUs from
Broadcom
Broadcom Inc. is an American designer, developer, manufacturer and global supplier of a wide range of semiconductor and infrastructure software products. Broadcom's product offerings serve the data center, networking, software, broadband, wirel ...
*
Transmeta
Transmeta Corporation was an American fabless semiconductor company based in Santa Clara, California. It developed low power x86 compatible microprocessors based on a VLIW core and a software layer called Code Morphing Software.
Code Morphing ...
TM8000 Efficeon CPUs
*
VIA
Via or VIA may refer to the following:
Science and technology
* MOS Technology 6522, Versatile Interface Adapter
* ''Via'' (moth), a genus of moths in the family Noctuidae
* Via (electronics), a through-connection
* VIA Technologies, a Taiwan ...
chipsets K8 series
Frequency specifications
* AMD
Athlon 64
The Athlon 64 is a ninth-generation, AMD64-architecture microprocessor produced by Advanced Micro Devices (AMD), released on September 23, 2003. It is the third processor to bear the name ''Athlon'', and the immediate successor to the Athlon XP. T ...
, Athlon 64 FX,
Athlon 64 X2
The Athlon 64 X2 is the first native dual-core desktop central processing unit (CPU) designed by Advanced Micro Devices (AMD). It was designed from scratch as native dual-core by using an already multi-CPU enabled Athlon 64, joining it with ano ...
, Athlon X2,
Athlon II
Athlon II is a family of AMD multi-core 45 nm central processing units, which is aimed at the budget to mid-range market and is a complementary product lineup to the Phenom II.
Features
The Athlon II series is based on the AMD K10 architect ...
, Phenom,
Phenom II
Phenom II is a family of AMD's multi-core 45 nm processors using the AMD K10 microarchitecture, succeeding the original Phenom. Advanced Micro Devices released the Socket AM2+ version of Phenom II in December 2008, while Socket AM3 versions w ...
,
Sempron
Sempron has been the marketing name used by AMD for several different budget desktop CPUs, using several different technologies and CPU socket formats. The Sempron replaced the AMD Duron processor and competed against Intel's Celeron series of pr ...
,
Turion series and later use one 16-bit HyperTransport link. AMD Athlon 64 FX (
1207),
Opteron
Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64 or AMD64). It was released on April 22, 2003, with the ''Sledg ...
use up to three 16-bit HyperTransport links. Common clock rates for these processor links are 800 MHz to 1 GHz (older single and multi socket systems on 754/939/940 links) and 1.6 GHz to 2.0 GHz (newer single socket systems on AM2+/AM3 links—most newer CPUs using 2.0GHz). While HyperTransport itself is capable of 32-bit width links, that width is not currently utilized by any AMD processors. Some chipsets though do not even utilize the 16-bit width used by the processors. Those include the Nvidia
nForce3
The nForce3 chipset was created by Nvidia as a Media and Communications Processor. Specifically, it was designed for use with the Athlon 64 processor.
Features of the nForce3
When the Athlon 64 was launched, the Nvidia nForce3 Pro150 and ...
150, nForce3 Pro 150, and the
ULi
Uli may refer to:
*Uli, Iran, a village
*Uli, Anambra, a town in Nigeria
* Uli I of Mali
* Uli (design), by the Igbo people of Nigeria
* Uli figure, from New Ireland, Papua New Guinea
*Uli (food), a rice-based food
* ISO 639 code for the Ulithian ...
M1689—which use a 16-bit HyperTransport downstream link but limit the HyperTransport upstream link to 8 bits.
Name
There has been some marketing confusion between the use of HT referring to HyperTransport and the later use of HT to refer to
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
's
Hyper-Threading
Hyper-threading (officially called Hyper-Threading Technology or HT Technology and abbreviated as HTT or HT) is Intel's proprietary simultaneous multithreading (SMT) implementation used to improve parallelization of computations (doing multip ...
feature on some
Pentium 4
Pentium 4 is a series of single-core CPUs for desktops, laptops and entry-level servers manufactured by Intel. The processors were shipped from November 20, 2000 until August 8, 2008. The production of Netburst processors was active from 2000 ...
-based and the newer Nehalem and Westmere-based
Intel Core
Intel Core is a line of streamlined midrange consumer, workstation and enthusiast computer central processing units (CPUs) marketed by Intel Corporation. These processors displaced the existing mid- to high-end Pentium processors at the time ...
microprocessors. Hyper-Threading is officially known as Hyper-Threading Technology (HTT) or HT Technology. Because of this potential for confusion, the HyperTransport Consortium always uses the written-out form: "HyperTransport."
Infinity Fabric
Infinity Fabric (IF) is a superset of HyperTransport announced by AMD in 2016 as an interconnect for its GPUs and CPUs. It is also usable as interchip interconnect for communication between CPUs and GPUs (for
Heterogeneous System Architecture Heterogeneous System Architecture (HSA) is a cross-vendor set of specifications that allow for the integration of central processing units and graphics processors on the same bus, with shared memory and tasks. The HSA is being developed by the HSA ...
), an arrangement known as Infinity Architecture. The company said the Infinity Fabric would scale from 30GB/s to 512GB/s, and be used in the
Zen
Zen ( zh, t=禪, p=Chán; ja, text= 禅, translit=zen; ko, text=선, translit=Seon; vi, text=Thiền) is a school of Mahayana Buddhism that originated in China during the Tang dynasty, known as the Chan School (''Chánzong'' 禪宗), and ...
-based CPUs and
Vega
Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, an ...
GPUs which were subsequently released in 2017.
On Zen and
Zen+
Zen ( zh, t=禪, p=Chán; ja, text= 禅, translit=zen; ko, text=선, translit=Seon; vi, text=Thiền) is a school of Mahayana Buddhism that originated in China during the Tang dynasty, known as the Chan School (''Chánzong'' 禪宗), and ...
CPUs, the "SDF" data interconnects are run at the same frequency as the DRAM memory clock (MEMCLK), a decision made to remove the latency caused by different clock speeds. As a result, using a faster RAM module makes the entire bus faster. The links are 32-bit wide, as in HT, but 8 transfers are done per cycle (128-bit packets) compared to the original 2. Electrical changes are made for higher power efficiency. On
Zen 2
Zen 2 is a computer processor microarchitecture by AMD. It is the successor of AMD's Zen and Zen+ microarchitectures, and is fabricated on the 7 nanometer MOSFET node from TSMC. The microarchitecture powers the third generation of Ryzen proce ...
and
Zen 3
Zen 3 is the codename for a CPU microarchitecture by AMD, released on November 5, 2020. It is the successor to Zen 2 and uses TSMC's 7 nm process for the chiplets and GlobalFoundries's 14 nm process for the I/O die on the server chips and 12 nm ...
CPUs, the IF bus is on a separate clock, either in a 1:1 or 2:1 ratio to the DRAM clock, because of Zen's early problems with high-speed DRAM affecting IF speed, and therefore system stability. The bus width has also been doubled.
See also
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Elastic interface bus Elastic interface buses, abbreviated as EI bus connections, can be generalized as bus connections which are high speed interfaces that send clock signals with data.
Description
The data bits that are sent through EI bus connections are aligned to ...
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Fibre Channel
Fibre Channel (FC) is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data cen ...
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Front-side bus
A front-side bus (FSB) is a computer communication interface (bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between the ...
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Intel QuickPath Interconnect
The Intel QuickPath Interconnect (QPI) is a point-to-point microprocessor, processor electrical connection, interconnect developed by Intel which replaced the front-side bus (FSB) in Xeon, Itanium, and certain desktop platforms starting in 2008. I ...
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List of device bandwidths
This is a list of interface bit rates, is a measure of information transfer rates, or digital bandwidth capacity, at which digital interfaces in a computer or network can communicate over various kinds of buses and channels. The distinction can ...
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PCI Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common ...
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RapidIO
The RapidIO architecture is a high-performance packet-switched electrical connection technology. RapidIO supports messaging, read/write and cache coherency semantics. Based on industry-standard electrical specifications such as those for Ether ...
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AGESA
References
External links
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{{Computer-bus
Computer buses
Macintosh internals
Serial buses