pctechguide.com

  • Home
  • Guides
  • Tutorials
  • Articles
  • Reviews
  • Glossary
  • Contact

DDR2 DRAM

The transition from DDR to DDR2 memory was more evolutionary than revolutionary, the DDR2 architecture being essentially the same as that of its predecessor, with a number of enhancements designed to provide greater bandwidth and other features that help reduce power consumption:

  • Higher memory transfer rates: DDR2 supports higher-speed transfer rates than DDR, which is officially found in 266 megatransfers per second (MTps), 333 MTps, and 400 MTps versions. Current DDR2 industry specifications call for 400 MTps, 533 MTps, 667 MTps and 800 MTps.
  • 4n prefetch: DDR2 devices use a 4n prefetch architecture instead of the 2n prefetch used for DDR. Using DDR2, the internal DRAM core is designed to read or write data at four times the width of the device’s external interface. In comparison, using DDR the internal DRAM core is designed to read or write data at twice the width of the device’s external interface. As a result, the internal DRAM core’s 4n prefetch architecture enables DDR2 to attain higher memory transfer rates than DDR.
  • Reduced voltage: DDR2 devices use a supply voltage of 1.8 volts versus 2.5 volts for DDR – almost a 30 percent decrease in supply voltage. This voltage scaling enhancement has the potential to reduce overall power requirements for the memory subsystem.

DDR2 memories work with higher latencies than DDR memories, meaning that they delay more clock cycles to deliver a requested item of data. For this reason, the performance advantage of DDR2 over DDR was not fully seen in practice until the emergence of DDR2-533 versions, in mid-2004.

DDR2

DDR2 is not backward compatible with DDR. Although DDR2 modules are the same length as DDR modules, differences exist in connectors, signalling, and supply voltages. For example, on DDR memories the resistive termination necessary for making the memory work is located on the motherboard, while on DDR2 memories this circuit is located inside the memory chip itself. Also, DDR modules have 184 contacts, while DDR2 modules have 240. Thus it is not possible to install DDR2 memories in DDR sockets or vice-versa.

The following table shows the bus frequency, data transfer rate, and bandwidth associated with each type of DDR2 module:

DDR2 type Module 

speed grade

Data 

transfer rate

Bandwidth 

(per channel)

DDR2 at 400MHz PC2-3200 200 MHz 400 MTps 3.2 GBps
DDR2 at 533 MHz PC2-4300 266 MHz 533 MTps 4.3 GBps
DDR2 at 667 MHz PC2-5300 333 MHz 667 MTps 5.3 GBps
DDR2 at 800 MHz PC2-6400 400 MHz 800 MTps 6.4 GBps

As processor power increased relentlessly – both by means of increased clock rates and wider FSBs – chipset manufacturers were quick to embrace the benefits of a dual-channel memory architecture as a solution to the growing bandwidth imbalance.

  • What is Level 1 (L1) Cache Memory?
  • What is L2 (Level 2) cache memory?
  • RAM or Main Memory – PC / computer memory (DIMM, DRAM, SDRAM)
  • DRAM – Dynamic Random Access Memory
  • FPM DRAM
  • EDO (Extended Data Out) and BEDO (Burst Extended Data Out) DRAM
  • SDRAM
  • PC133 SDRAM
  • DDR SDRAM explained
  • DDR2 DRAM
  • Dual Channel DDR Memory
  • 1T SRAM
  • Direct DRAM
  • SIMMs
  • DIMM Memory
  • RIMMs Memory
  • Memory Presence Detection
  • Parity Memory
  • ECC Memory
  • Memory Upgrades
  • The Evolution of Memory
  • Flash Memory
  • Magnetic RAM

Filed Under: Computer Memory

Latest Articles

What is LightFrame Technology?

CRT monitors and TVs have each been optimised for the applications they've been traditionally used for. The former excel at displaying close-up high-resolution content, such as text, while lower-resolution TV screens' larger dot pitch and … [Read More...]

5 Ways to Increase Computer Security

Though the internet is far safer now than it was in its infancy, there are nevertheless more people using the net than ever and this means that there is a much greater field of victims for the cunning hacker or identity thief. Even major corporations, who spend millions each year in computer … [Read More...]

The Google Nexus 7 4G LTE Tablet

Now, Google Nexus 7 4G LTE Tablet brings in the best integration of portability, power and the sharpness for a 7 inch tablet screen can offer. It has a simple and clean design for a slim casing, with a thin edge-soft to touch, and a matte back cover. Enjoy the Features New slim design It … [Read More...]

AI-Driven Software Improves Trading Strategies for Investors

Artificial intelligence technology is changing the state of modern finance. A growing number of investors are utilizing AI to improve the … [Read More...]

What You Need to Know When Choosing the Best VPN for an iPhones

Today millions of people have smartphones; most use them to access the Internet. Research shows that more than 50% of Internet users access it with … [Read More...]

Must-Have Software and Apps Every Remote Worker Should Have on Their PC in 2023?

In the last few years, the future of work has changed permanently. In a survey conducted near the end of 2020, 72% of people were fully remote, with … [Read More...]

Cloud Technology Changes the Calculus of Risk Management in a Global Economy

Cloud technology has changed the state of the global economy in previously unimaginable ways. Ninety-four percent of enterprises utilize some form of … [Read More...]

Risk Management Considerations in an Artificial Intelligence Environment

Risk management is about identifying, assessing, evaluating, and prioritizing risk. Although risk management has been practiced in some ways since … [Read More...]

New Software and GPS Tools Help Parents Monitor their Children

More parents are using technology to keep their children safe. One survey from Pew Research in 2016 showed that 30% of parents use technology to block … [Read More...]

Guides

  • Computer Communications
  • Mobile Computing
  • PC Components
  • PC Data Storage
  • PC Input-Output
  • PC Multimedia
  • Processors (CPUs)

Recent Posts

Identifying and Protecting Against the Most Dangerous Keyloggers

Keyloggers are among the most frightening tools in the hands of a skilled hacker. They are malicious devices or malware applications that enable … [Read More...]

Google Chrome Shortcuts

Google Chrome is a very popular Web browser. It is my browser of choice because it is fast and secure. It is also very flexible and comes with many … [Read More...]

Guide to PowerNow! – AMD’s dynamic power management technology

PowerNow! is effectively AMD's version of Intel's SpeedStep technology. The premise is a simple one: some applications … [Read More...]

[footer_backtotop]

Copyright © 2023 About | Privacy | Contact Information | Wrtie For Us | Disclaimer | Copyright License | Authors