Hardware Secrets
Home | Camera | Case | CE | Cooling | CPU | Input | Memory | Mobile | Motherboard | Networking | Power | Storage | Video | Other
First Look
Gabriel’s Blog
Main Menu
About Us
Awarded Products
Manufacturer Finder
RSS Feed
Test Your Skills
Subscribe today!
Upgrading and Repairing PCs (21st Edition)
Upgrading and Repairing PCs (21st Edition), by Scott Mueller (Que Publishing), starting at $23.35

Home » Memory
Everything You Need to Know About the Dual-, Triple-, and Quad-Channel Memory Architectures
Author: Gabriel Torres 846,172 views
Type: Tutorials Last Updated: November 2, 2011
Page: 1 of 9

The system’s RAM (Random Access Memory) prevents the PC from achieving its maximum capable performance. This occurs because the processor (CPU) is faster than the RAM, and usually it has to wait for the RAM to deliver data. During this wait time the CPU is idle, doing nothing (that’s not entirely true, but it fits our explanation). In a perfect computer, the RAM would be as fast as the CPU. Dual-, triple-, and quad-channel are techniques used to double, triple, or quadruple the communication speed between the memory controller and the RAM, thus increasing the system performance. In this tutorial, we will explain everything you need to know about these technologies: how they work, how to set them up, how to calculate transfer speeds, and more.

Before going further, let’s first explain how the RAM is traditionally connected to the system.

The RAM is controlled by a circuit called a memory controller. Currently, most processors have this component embedded, so the CPU has a dedicated memory bus connecting the processor to the RAM. On older CPUs, however, this circuit was located inside the motherboard chipset, in the north bridge chip. (This chip is also known as MCH or Memory Controller Hub.) In this case, the CPU doesn’t “talk” directly to the RAM; the CPU “talks” to the north bridge chip, and this chip “talks” to the memory. The first option provides better performance, since there is no “middleman” in the communications between the CPU and the memory. In Figures 1 and 2, we compare the two approaches.

How the RAM is accessed on CPUs with an integrated memory controller
click to enlarge
Figure 1: How the RAM is accessed on CPUs with an integrated memory controller

How the RAM is accessed on CPUs without an integrated memory controller
click to enlarge
Figure 2: How the RAM is accessed on CPUs without an integrated memory controller

The RAM is connected to the memory controller through a series of wires, collectively known as a “memory bus.” These wires are divided into three groups: data, address, and control. The wires from the data bus will carry data that is being read (transferred from the memory to the memory controller) or written (transferred from the memory controller to the memory, i.e., coming out of the CPU). The wires from the address bus tell the memory modules exactly where (which address) that data must be retrieved or stored. The control wires send commands to the memory modules, telling them what kind of operation is being done – for example, if it is a write (store) or a read operation. Another important wire present on the control bus is the memory clock signal.

The memory speeds (clock rates), maximum capacity per memory module, total maximum capacity, and types (DDR, DDR2, DDR3, etc.) that a system can accept is defined by the memory controller. For example, if a given memory controller only supports DDR3 memories up to 1,333 MHz, you won’t be able to install DDR2 memories, and if you install DDR3 memories above 1,333 MHz (e.g., 1,866 MHz or 2,133 MHz modules), they will be accessed at 1,333 MHz. (An exception to this rule is when the motherboard allows you to configure the RAM at a clock rate above the official maximum supported by the memory controller. For a real example, current Intel CPUs support memories up to 1,333 MHz, but several motherboards will allow you to configure clock rates up to 2,133 MHz.)

The discussion about clock rates is really important, because the clock rate defines the available bandwidth, which is our next subject.

Print Version | Send to Friend | Bookmark Article Page 1 of 9  | Next »

Related Content
  • Understanding RAM Timings
  • Memory Overclocking
  • Everything You Need To Know About DDR, DDR2 and DDR3 Memories
  • DDR vs. GDDR Memories
  • How FB-DIMM Memories Work

  • RSSLatest Content
    Core i7-5960X CPU Review
    February 24, 2015 - 3:00 AM
    ASUS ZenFone 6 Smartphone Review
    January 23, 2015 - 4:15 AM
    WD My Cloud 3 TB Network HDD Review
    January 19, 2015 - 4:30 AM
    AMD Athlon 5150 CPU Review
    January 12, 2015 - 5:30 AM
    Pentium J2900 CPU Review
    January 7, 2015 - 5:00 AM
    ASRock Q2900M Motherboard
    January 6, 2015 - 2:26 AM
    ASRock Z97 Anniversary Motherboard
    December 16, 2014 - 4:27 AM

    2004-15 Clube do Hardware, all rights reserved.
    Advertising | Legal Information | Privacy Policy
    All times are Pacific Standard Time (PST, GMT -08:00)