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. This is in contrast to analog electronics and analog signals.
Digital electronic circuits are usual ...
and
computer hardware
Computer hardware includes the physical parts of a computer, such as the computer case, case, central processing unit (CPU), Random-access memory, random access memory (RAM), Computer monitor, monitor, Computer mouse, mouse, Computer keyboard, ...
, multi-channel memory architecture is a technology that increases the data transfer rate between the
DRAM
Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxid ...
memory and the
memory controller
The memory controller is a digital circuit that manages the flow of data going to and from the computer's main memory. A memory controller can be a separate chip or integrated into another chip, such as being placed on the same die or as an int ...
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 IBM ...
.
Modern high-end desktop and workstation processors such as the
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 ...
Ryzen Threadripper
Ryzen ( ) is a brand of multi-core x86-64 microprocessors designed and marketed by AMD for desktop, mobile, server, and embedded platforms based on the Zen microarchitecture. It consists of central processing units (CPUs) marketed for mainst ...
series and the
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 ...
Core i9 Extreme Edition lineup support quad-channel memory. Server processors from the AMD
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 t ...
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 system markets. It was introduced in June 1998. Xeon processors are based on the same arc ...
platforms give support to memory bandwidth starting from quad-channel module layout to up to octa-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. S ...
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
LGA 771, also known as ''Socket J'', is a CPU interface introduced by Intel in 2006. It is used in Intel Core (microarchitecture), Core microarchitecture and NetBurst (microarchitecture), NetBurst microarchitecture(Dempsey) based DP-capable ser ...
platform and later in 2011 for its
LGA2011
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. 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 as a backbo ...
of the machine limited operation to four channels.
Dual-channel architecture
![Dual channel slots](https://upload.wikimedia.org/wikipedia/commons/b/b3/Dual_channel_slots.jpg)
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, 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 ...
(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
DDR or ddr may refer to:
*ddr, ISO 639-3 code for the Dhudhuroa language
*DDr., title for a double doctorate in Germany
*DDR, station code for Dadar railway station, Mumbai, India
*' (German Democratic Republic), official name of the former East ...
,
DDR2,
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 ("double data rate") interface, and has been in use since 2007. It is the higher-speed ...
,
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 ...
, or
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
Double Data Rate 4 Synchronous Dynamic Random-Access Memory (DDR4 SDRAM) ...
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.
* Same CAS Latency (CL) or Column Address Strobe.
* Number of chips and sides (e.g. two sides with four chips on each side).
* Matching size of rows and columns.
Dual-channel architecture is a technology implemented on motherboards by the motherboard manufacturer and does not apply to memory modules. Theoretically any matched pair of memory modules may be used in either single- or dual-channel operation, provided the motherboard supports this architecture.
Performance
Theoretically, dual-channel configurations double the memory bandwidth when compared to single-channel configurations. This should not be confused with
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 ...
(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.
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.
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 is a microprocessor on a single integrated circuit with two or more separate processing units, called cores, each of which reads and executes program instructions. The instructions are ordinary CPU instructions (such a ...
s.
"Ganged" versus "unganged" difference could also be envisioned as an analogy with the way
RAID 0
In computer storage, the standard RAID levels comprise a basic set of RAID ("redundant array of independent disks" or "redundant array of inexpensive disks") configurations that employ the techniques of striping, mirroring, or parity to create lar ...
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 ("double data rate") interface, and has been in use since 2007. It is the higher-speed ...
triple-channel architecture is used in the
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 ...
Core i7
The following is a list of Intel Core i7 brand microprocessors. Introduced in 2008, the Core i7 line of microprocessors are intended to be used by high-end users.
Desktop processors
Nehalem microarchitecture (1st generation)
"Bloomfield" ...
-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
The following is a list of Intel Core i5 brand microprocessors. Introduced in 2009, the Core i5 line of microprocessors are intended to be used by mainstream users.
Desktop processors
Nehalem microarchitecture (1st generation)
"Lynnf ...
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. Its incompatible successor is LGA 1155.
The last processors supporting it ceased production in 2011.
LGA 1156, along with LGA 1366, were designed t ...
platforms (e.g.,
Intel P55
The Intel P55 is the first desktop chipset from Intel based on the PCH chipset design. The P55 Express chipset uses the LGA 1156 socket. Compatible CPUs include the first generation Core i series i3, i5, and i7 processor line along with a Pen ...
). 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 consume ...
.
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 hav ...
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
LGA 1567 or Socket LS, is a CPU socket used for the high-end server segment. It has 1567 protruding pins to make contact with the pads on the processor. It supports Intel Nehalem (microarchitecture), Nehalem, codenamed Beckton (microprocessor), Be ...
platform of Xeon CPUs, aka Beckton in 2010, and was introduced to the high end product line on the Intel X79
The Intel X79 ( codenamed ''Patsburg'') is a Platform Controller Hub (PCH) designed and manufactured by Intel for their LGA 2011 (Socket R) and LGA 2011-1 (Socket R2).
Socket and chipset support CPUs targeted at the high-end desktop (HEDT) and en ...
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 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 ("double data rate") interface, and has been in use since 2007. It is the higher-speed ...
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 ...
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, aka Haswell-E, and is also used in AMD's Threadripper
Ryzen ( ) is a brand of multi-core x86-64 microprocessors designed and marketed by AMD for desktop, mobile, server, and embedded platforms based on the Zen microarchitecture. It consists of central processing units (CPUs) marketed for mainstr ...
platform. 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 ("double data rate") interface, and has been in use since 2007. It is the higher-speed ...
quad-channel architecture is used in the 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 ...
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 (2nd Gen) and Ivy Bridge (3rd Gen) microarchitectures.
It is the successor of L ...
platform (e.g. Intel Z68
This article provides a list of motherboard chipsets made by Intel, divided into three main categories: those that use the Peripheral Component Interconnect, PCI bus for interconnection (the 4xx series), those that connect using specialized "hub ...
) 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.
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 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 t ...
platform, and the Threadripper PRO lineup of professional-class workstation processors from AMD Ryzen PRO product family.
See also
* 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 ...
* Lockstep (computing)
Lockstep systems are fault-tolerant computer systems that run the same set of operations at the same time in parallel. The redundancy (duplication) allows error detection and error correction: the output from lockstep operations can be compared ...
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
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