In the fields of

digital electronics Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. It deals with the relationship between Binary number, binary inputs and outputs by passing electrical s ...

and

computer hardware Computer hardware includes the physical parts of a computer, such as the central processing unit (CPU), random-access memory (RAM), motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices ...

, multi-channel memory architecture is a technology that increases the data transfer rate between the

DRAM Dram, DRAM, or drams may refer to: Technology and engineering * Dram (unit), a unit of mass and volume, and an informal name for a small amount of liquor, especially whisky or whiskey * Dynamic random-access memory, a type of electronic semicondu ...

memory and the

memory controller A memory controller, also known as memory chip controller (MCC) or a memory controller unit (MCU), is a digital circuit that manages the flow of data going to and from a computer's main memory. When a memory controller is integrated into anothe ...

by adding more channels of communication between them. Theoretically, this multiplies the data rate by exactly the number of channels present. Dual-channel memory employs two channels. The technique goes back as far as the 1960s having been used in

IBM System/360 Model 91 The IBM System/360 Model 91 was announced in 1964 as a competitor to the CDC 6600. Functionally, the Model 91 ran like any other large-scale System/360, but the internal organization was the most advanced of the System/360 line, and it was the ...

and in

CDC 6600 The CDC 6600 was the flagship of the 6000 series of mainframe computer systems manufactured by Control Data Corporation. Generally considered to be the first successful supercomputer, it outperformed the industry's prior recordholder, the I ...

. Modern high-end desktop and workstation processors such as the

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational corporation and technology company headquartered in Santa Clara, California and maintains significant operations in Austin, Texas. AMD is a hardware and fabless company that de ...

Ryzen Threadripper Threadripper, or Ryzen Threadripper, is a brand of HEDT (high-end desktop) and workstation multi-core x86-64 microprocessors designed and marketed by Advanced Micro Devices (AMD), and based on the Zen microarchitecture. It consists of central pro ...

series and the

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

Core i9 Extreme Edition lineup support quad-channel memory. Server processors from the AMD

Epyc Epyc (stylized as 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 market ...

series and the Intel

Xeon Xeon (; ) is a brand of x86 microprocessors designed, manufactured, and marketed by Intel, targeted at the non-consumer workstation, server, and embedded markets. It was introduced in June 1998. Xeon processors are based on the same archite ...

platforms give support to memory bandwidth starting from quad-channel module layout to up to 12-channel layout. In March 2010, AMD released

Socket G34 Socket G34 is a land grid array CPU socket designed by AMD to support AMD's multi-chip module Opteron 6000-series server processors. G34 was launched on March 29, 2010, alongside the initial grouping of Opteron 6100 processors designed for it. So ...

and Magny-Cours Opteron 6100 series processors with support for quad-channel memory. In 2006, Intel released chipsets that support quad-channel memory for its LGA771 platform and later in 2011 for its LGA2011 platform. Microcomputer chipsets with even more channels were designed; for example, the chipset in the

AlphaStation AlphaStation is the name given to a series of computer workstations, produced from 1994 onwards by Digital Equipment Corporation, and later by Compaq and HP. As the name suggests, the AlphaStations were based on the DEC Alpha 64-bit microproce ...

600 (1995) supports eight-channel memory, but the

backplane A backplane or backplane system is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used to connect s ...

of the machine limited operation to four channels.

Dual-channel architecture

Dual-channel-enabled memory controllers in a PC system architecture use two 64-bit data channels. Dual-channel should not be confused with

double data rate In computing, double data rate (DDR) describes a computer bus that transfers data on both the rising and falling edges of the clock signal and hence doubles the memory bandwidth by transferring data twice per clock cycle. This is also known a ...

(DDR), in which data exchange happens twice per DRAM clock. The two technologies are independent of each other, and many motherboards use both by using DDR memory in a dual-channel configuration.

Operation

Dual-channel architecture requires a dual-channel-capable motherboard and two or more DDR memory modules. The memory modules are installed into matching banks, each of which belongs to a different channel. The motherboard's manual will provide an explanation of how to install memory for that particular unit. A matched pair of memory modules may usually be placed in the first bank of each channel, and a different-capacity pair of modules in the second bank. Modules rated at different speeds can be run in dual-channel mode, although the motherboard will then run all memory modules at the speed of the slowest module. Some motherboards, however, have compatibility issues with certain brands or models of memory when attempting to use them in dual-channel mode. For this reason, it is generally advised to use identical pairs of memory modules, which is why most memory manufacturers now sell "kits" of matched-pair DIMMs. Several motherboard manufacturers only support configurations where a "matched pair" of modules are used. A matching pair needs to match in: * Capacity (e.g. 1024 MB). Certain Intel chipsets support different capacity chips in what they call Flex Mode: the capacity that can be matched is run in dual-channel, while the remainder runs in single-channel. * Speed (e.g. PC5300). If speed is not the same, the lower speed of the two modules will be used. Likewise, the higher latency of the two modules will be used. * CAS (Column Address Strobe) latency, or CL. * Number of chips and sides (e.g. two sides with four chips on each side). * Size of rows and columns. Theoretically any matched pair of memory modules may be used in either single- or dual-channel operation, provided the motherboard supports this architecture. With the introduction of

DDR5 Double Data Rate 5 Synchronous Dynamic Random-Access Memory (DDR5 SDRAM) is a type of synchronous dynamic random-access memory. Compared to its predecessor DDR4 SDRAM, DDR5 was planned to reduce power consumption, while doubling bandwidth. The ...

, each DDR5 DIMM has two independent sub-channels.

Performance

Theoretically, dual-channel configurations double the memory bandwidth when compared to single-channel configurations. This should not be confused with

(DDR) memory, which doubles the usage of DRAM bus by transferring data both on the rising and falling edges of the memory bus clock signals.

Ganged versus unganged

Dual-channel was originally conceived as a way to maximize memory throughput by combining two 64-bit buses into a single 128-bit bus. This is retrospectively called the "ganged" mode. However, due to lackluster performance gains in consumer applications, more modern implementations of dual-channel use the "unganged" mode by default, which maintains two 64-bit memory buses but allows independent access to each channel, in support of multithreading with

multi-core processor A multi-core processor (MCP) is a microprocessor on a single integrated circuit (IC) with two or more separate central processing units (CPUs), called ''cores'' to emphasize their multiplicity (for example, ''dual-core'' or ''quad-core''). Ea ...

s. "Ganged" versus "unganged" difference could also be envisioned as an analogy with the way RAID 0 works, when compared to

JBOD The most widespread standard for configuring multiple hard disk drives is RAID (redundant array of inexpensive/independent disks), which comes in a number of standard configurations and non-standard configurations. Non-RAID drive architectures a ...

. With RAID 0 (which is analogous to "ganged" mode), it is up to the additional logic layer to provide better (ideally even) usage of all available hardware units (storage devices, or memory modules) and increased overall performance. On the other hand, with JBOD (which is analogous to "unganged" mode) it is relied on the statistical usage patterns to ensure increased overall performance through even usage of all available hardware units.

Triple-channel architecture

Operation

DDR3 Double Data Rate 3 Synchronous Dynamic Random-Access Memory (DDR3 SDRAM) is a type of synchronous dynamic random-access memory (SDRAM) with a high Bandwidth (computing), bandwidth ("double data rate") interface, and has been in use since 2007. ...

triple-channel architecture is used in the

Core i7 Intel Core is a line of multi-core (with the exception of Core Solo and Core 2 Solo) central processing units (CPUs) for midrange, embedded, workstation, high-end and enthusiast computer markets marketed by Intel Corporation. These processors ...

-900 series (the Intel Core i7-800 series only support up to dual-channel). The LGA 1366 platform (e.g. Intel X58) supports DDR3 triple-channel, normally 1333 and 1600Mhz, but can run at higher clock speeds on certain motherboards. AMD Socket AM3 processors do not use the DDR3 triple-channel architecture but instead use dual-channel DDR3 memory. The same applies to the Intel Core i3, Core i5 and Core i7-800 series, which are used on the

LGA 1156 LGA 1156 (land grid array 1156), also known as Socket H or H1, is an Intel desktop CPU socket. The last processors supporting the LGA 1156 ceased production in 2011. It was succeeded by the mutually incompatible socket LGA 1155. LGA 1156, alon ...

platforms (e.g., Intel P55). According to Intel, a Core i7 with DDR3 operating at 1066 MHz will offer peak data transfer rates of 25.6 GB/s when operating in triple-channel interleaved mode. This, Intel claims, leads to faster system performance as well as higher

performance per watt In computing, performance per watt is a measure of the energy efficiency of a particular computer architecture or computer hardware. Literally, it measures the rate of computation that can be delivered by a computer for every watt of power con ...

. When operating in triple-channel mode,

memory latency ''Memory latency'' is the time (the latency) between initiating a request for a byte or word in memory until it is retrieved by a processor. If the data are not in the processor's cache, it takes longer to obtain them, as the processor will ha ...

is reduced due to interleaving, meaning that each module is accessed sequentially for smaller bits of data rather than completely filling up one module before accessing the next one. Data is spread amongst the modules in an alternating pattern, potentially tripling available memory bandwidth for the same amount of data, as opposed to storing it all on one module. The architecture can only be used when all three, or a multiple of three, memory modules are identical in capacity and speed, and are placed in three-channel slots. When two memory modules are installed, the architecture will operate in dual-channel architecture mode.,
Single- and Multichannel Memory Modes
/ref>

Supporting processors

Intel Core i7: * Intel Core i7-9xx Bloomfield, Gulftown * Intel Core i7-9x0X Gulftown Intel Xeon: * Intel Xeon E55xx Nehalem-EP * Intel Xeon E56xx Westmere-EP * Intel Xeon ECxxxx Jasper Forest * Intel Xeon L55xx Nehalem-EP * Intel Xeon L5609 Westmere-EP * Intel Xeon L5630 Westmere-EP * Intel Xeon L5640 Westmere-EP * Intel Xeon LC55x8 Jasper Forest * Intel Xeon Wxxxx Bloomfield, Nehalem-EP, Westmere-EP * Intel Xeon X55xx Nehalem-EP * Intel Xeon X56xx Westmere-EP * Intel Xeon x4xx v3 * Intel Pentium 14xx v3 * Intel Xeon x4xx v2 * Intel Pentium 14xx v2 * Intel Xeon x4xx * Intel Pentium 14xx

Quad-channel architecture

Operation

Quad-channel memory debuted on Intel's Nehalem-EX LGA 1567 platform of Xeon CPUs, aka Beckton in 2010, and was introduced to the high end product line on the Intel X79

LGA 2011 LGA 2011, also called ''Socket R'', is a CPU socket by Intel released on November 14, 2011. It launched along with LGA 1356 to replace its predecessor, LGA 1366 (Socket B) and LGA 1567. While LGA 1356 was designed for dual-processor or ...

platform with Sandy Bridge-E in late 2011.

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 rando ...

replaced

on the

Intel X99 Intel X99, codenamed "Wellsburg", is a Platform Controller Hub (PCH) designed and manufactured by Intel, targeted at the high-end desktop (HEDT) and enthusiast segments of the Intel product lineup. The X99 chipset supports both Intel Core&n ...

platform, aka Haswell-E, and is also used in AMD's

Threadripper Threadripper, or Ryzen Threadripper, is a brand of HEDT (high-end desktop) and workstation multi-core x86-64 microprocessors designed and marketed by Advanced Micro Devices (AMD), and based on the Zen microarchitecture. It consists of central pro ...

platform.

quad-channel architecture is used in the

G34 platform and in the aforementioned Intel CPUs prior to Haswell. AMD processors for the C32 platform and Intel processors for the

LGA 1155 LGA 1155, also called Socket H2, is a zero insertion force flip-chip land grid array (LGA) CPU socket designed by Intel for their CPUs based on the Sandy Bridge (second generation core) and Ivy Bridge (microarchitecture), Ivy Bridge (third gen ...

platform (e.g. Intel Z68) use dual-channel DDR3 memory instead. The architecture can be used only when all four memory modules (or a multiple of four) are identical in capacity and speed, and are placed in quad-channel slots. When two memory modules are installed, the architecture will operate in a dual-channel mode; When three memory modules are installed, the architecture will operate in a triple-channel mode.

Performance

A benchmark performed by TweakTown, using SiSoftware Sandra, measured around 70% increase in performance of a quadruple-channel configuration, when compared to a dual-channel configuration. Other tests performed by TweakTown on the same subject showed no significant differences in performance, leading to a conclusion that not all benchmark software is up to the task of exploiting increased parallelism offered by the multi-channel memory configurations.

Supporting processors

AMD Threadripper: * AMD Ryzen Threadripper 3rd gen 3990X * AMD Ryzen Threadripper 3rd gen 3970X * AMD Ryzen Threadripper 3rd gen 3960X * AMD Ryzen Threadripper 2nd gen 2990WX * AMD Ryzen Threadripper 2nd gen 2970WX * AMD Ryzen Threadripper 2nd gen 2950X * AMD Ryzen Threadripper 2nd gen 2920X * AMD Ryzen Threadripper 1950X * AMD Ryzen Threadripper 1920X * AMD Ryzen Threadripper 1900X AMD Epyc: * Epyc 7003 series processors * Epyc 7002 series processors * Epyc 7001 series processors AMD Opteron: * Opteron 6300-series "Abu Dhabi" (32 nm) * Opteron 6200-series "Interlagos" (32 nm) * Opteron 6100-series "Magny-Cours" (45 nm) Intel Core: * Intel Core i9-10900X * Intel Core i7-9800X * Intel Core i9-7980XE * Intel Core i9-7940X * Intel Core i9-7900X * Intel Core i7-7820X * Intel Core i7-7800X * Intel Core i7-6950X * Intel Core i7-6900K * Intel Core i7-6850K * Intel Core i7-6800K * Intel Core i7-5960X * Intel Core i7-5930K * Intel Core i7-5820K * Intel Core i7-4960X * Intel Core i7-4930K * Intel Core i7-4820K * Intel Core i7-3970X * Intel Core i7-3960X * Intel Core i7-3930K * Intel Core i7-3820 Intel Xeon: * Intel Xeon E5-x6xx v4 * Intel Xeon E7-x8xx v3 * Intel Xeon E5-x6xx v3 * Intel Xeon E7-x8xx v2 * Intel Xeon E5-x6xx v2 * Intel Xeon E7-x8xx * Intel Xeon E5-x6xx

Hexa-channel architecture

Supported by Qualcomm Centriq server processors, and processors from the Intel Xeon Scalable platform.

Octa-channel architecture

Supported by Cavium ThunderX2 server processors, AMD's server processors from their

platform, and the Threadripper PRO lineup of professional-class workstation processors.

Dodeca-channel architecture

Dodeca-channel or 12-channel memory architecture is introduced with AMD's server processors from their Epyc 9004 platform released in 2022, using

memory.

References

External links

* .
Everything You Need to Know About the Dual-, Triple-, and Quad-Channel Memory Architectures
November 2011, Hardware Secrets
Memory Configuration Guide for X9 Series DP Motherboards Revised Ivy Bridge Update (Socket R & B2)
January 2014, Super Micro Computer, Inc.
DDR3 Memory Frequency Guide
May 2012, AMD (archived) {{DEFAULTSORT:Multi-channel memory architecture Computer memory Intel x86 microprocessors ca:Dual channel de:Dual Channel de:Triple Channel es:Arquitectura de memoria multicanal it:Dual channel ja:デュアルチャネル pl:Dual channel

Dual-channel architecture

Operation

Performance

Ganged versus unganged

Triple-channel architecture

Operation

Supporting processors

Quad-channel architecture

Operation

Performance

Supporting processors

Hexa-channel architecture

Octa-channel architecture

Dodeca-channel architecture

See also

References

External links