Computer Memory Upgrade
Your guide to computer memory upgrades,
RAM buying guide, and guide to install compatible RAM.

Table of Contents

Frequently asked Questions on Memory (FAQs)

What are the benefits of upgrading computers memory?

Upgrading your memory is typically the easiest and least expensive way to upgrade your computer for a significant boost in performance. The computer's RAM memory is its workspace, or where all of the instructions it needs to act on are stored temporarily. Think of the RAM as the desk you use to sort through your work. If the size of that desk is small, your efficiency is limited in comparison to a larger desk that allows you to work more effectively and efficiently. Similarly, a computer with more RAM can work more efficiently because it does not need to retrieve information from the hard disk drive as often. A memory upgrade is particularly helpful for users who work with large files, have more than one program open at one time, or use memory-intensive applications such as games or graphics and video editing software.

How do you know it's time for a memory upgrade?

There are several signs indicating it may be time to upgrade your memory. If you see your mouse pointer turn into an hourglass for significant periods of time, if you hear your hard drive working, or if your computer seems to work more slowly than you expect, the reason is probably insufficient memory. When physical memory is insufficient, the system uses Hard Disk Space as memory. This is called "Virtual Memory". Since access time of Physical memory is in tens of NanoSeconds and Access time of Hard Disk is in MilliSeconds, the system slows down considerably.

DDR2 Memory Memory

DDR2 is the next-generation DDR memory technology which features faster speeds, higher data bandwidths, lower power consumption, and enhanced thermal performance.

Try  this site for recommendations on DDR and DDR2 Memory Upgrades

DDR2 Unbuffered DIMM ECC and Non-ECC ( 240pin)
For PC and low end workstations
Dimension approx. 5.25" x 1.18" (13.34cm x 2.99cm)

Registered ECC DIMMs ( 240 pin) 
For Server and high end workstations

Unbuffered DDR2 SODIMM ( 200pin)
For Laptop and Cube PC

MicroDIMM( 214 pin)
Micro-DIMM is a SO-DIMM with a smaller outline and thickness than standard SO-DIMMs. Therefore it is designed for sub-Notebooks applications which are mobile type, slim type and super light weight Notebooks.

Very small outline DIMM
Densities: 256MB, 512MB, 1GB
Based on Infineon's 512Mbit and 1Gb componentsSpeed: DDR2-400, DDR2-533

What is a DDR2 DIMM ?

A dual inline memory module (DIMM) consists of a number of memory components (usually black) that are attached to a printed circuit board (usually green). The gold pins on the bottom of the DIMM provide a connection between the module and a socket on a larger printed circuit board. The pins on the front and back of a DIMM are not connected to each other.


DDR2 memory modules are offered in two frequency range, 400MHz and 533MHz speeds (data rate) in 2004, and followed by 667MHz by Fall of 2005.


240-pin DIMMs are used to provide DDR2 SDRAM memory for desktop computers. Each DDR2 240-pin DIMM provides a 64-bit data path (72-bit for ECC or registered modules), so they are installed singly in 64-bit systems. Most DDR2 chipsets are expected to support dual-channel memory, effectively providing a 128-bit data path

DDR2 DIMM memory modules are not backward-compatible with DDR DIMM , due to incompatible pin configurations, core voltage, and memory chip technology. DDR2 modules are designed with a different "key" in the edge connector to prevent insertion into incompatible memory sockets such as DDR motherboard. A DDR2 SDRAM DIMM will not fit into a standard SDRAM DIMM socket or a DDR DIMM socket. DDR2 modules use a 1.8V power supply, providing a big power saving over the 2.5V DDR modules.


240-pin DIMMs are available in DDR2 PC2-4200 (DDR2-533) SDRAM or DDR2 PC2-3200 (DDR2-400) SDRAM. To use DDR2 memory, your system motherboard must have 240-pin DIMM slots and a DDR2-enabled chipset.


DDR2 Memory Chips

DDR2 memory can no longer be made into TSOP chips, and are offered FBGA (Fine-pitch Ball Grid Array) chips.


Memory Classifications

Memory Speed are offered in 400, 533 & 667Mhz

Memory Chip classification are named : DDR2-400 , DDR2-533Mhz and DDR2-667Mhz

Module DIMM Classificiation are named : PC2-3200 or 400Mhz) , PC2-4200 or 533 mhz and PC2-533 or 667Mhz

Module Bandwidth : PC2-3200 = 3.2 Gb/s , PC2-4200= 4.2 Gb/s & PC2-5300= 10.6 Gb/s

DDR2 was designed to overcome many of the problems with DDR:


DDR2 versus DDR Modules

DDR2 memory modules have basically the same dimensions as the DDR modules, but have different pin configurations, therefore DDR2 DIMM will not fit in the DDR memory slot.

The table compares the different types of modules for DDR and DDR2:




Unbuffered DIMM

240pin 1.8V

184pin 2.5V

Registered DIMM

240pin 1.8V

184pin 2.5V


200pin 1.8V

200pin 2.5V

Mini Registered DIMM

244pin 1.8V


214pin 1.8V

172pin 2.5V

Because of different voltages and pin configurations, DDR2 modules will have a different "key" or notch in their connector to prevent them from being plugged into an incompatible socket. DDR2 memory modules will only fit in systems and motherboards designed to specifically support DDR2 memory. The number of black components on a 240-pin DIMM may vary, but they always have 120 pins on the front and 120 pins on the back.While 240-pin DDR2 DIMMs, 184-pin DDR DIMMs and 168-pin DIMMs are approximately the same size, 240-pin DIMMs and 184-pin DIMMs have only one notch within the row of pins.

DDR3 Memory Modules Launched

Intel Bearlake P35 based desktop motherboards are  released for the very first time which support DDR3 memory. While these motherboards will feature the latest and greatest Intel P35 chipsets they also happen to be the first desktop platform that utilizes DDR3 memory modules. For those that don't know DDR3 Memory is the next generation of Double Data Rate (DDR) Synchronous Dynamic Random Access Memory (SDRAM). DDR3 memory modules are an improvement of DDR and DDR2 memory technology and will deliver higher clock frequencies, lower power consumption and as a result lower heat dissipation. When DDR3 is launched the frequencies will be at 1066Mhz and 1333Mhz, with 1600MHz and beyond out in the distance.

For those that recall the transition from DDR1 to DDR2, the move from DDR2 to DDR3 will be much the same. It will take years for DDR3 to become main stream with many predicting that it will take the industry till 2009 to fully moved over to the new memory form factor. Those with DDR2 motherboard have nothing to worry about as DDR2 production will continue with improved parts still on the drawing boards.

About three years ago DDR2 memory first appeared on the desktop PC scene. It would be impossible to say it burst on the scene since it was introduced with the unimpressive Intel NetBurst processors. In that market DDR2 was more like a trickle since it was mainly a curiosity for a processor that was running a distant second place to the leading AMD Athlon chips, which were still powered by DDR memory.

DDR2 finally became the universal standard last May/June when AMD switched to DDR2 on their new AM2 platform and Intel introduced Core 2 Duo, the new CPU performance leader. Core 2 Duo resided on socket 775, which also was fed by DDR2. While it sometimes seems like centuries ago, it is worth remembering that Intel Core 2 Duo regained the CPU performance crown less than a year ago, and the two years prior to that all the fastest systems used AMD Athlon 64/X2/FX processors.

Performance of DDR2 on the new platforms in July of last year. AM2 provided better bandwidth with DDR2, but the better AM2 bandwidth did not translate into better performance. Since Core 2 Duo was faster at the same timings, it appeared the Intel Core 2 Duo architecture was not particularly bandwidth hungry and that it made very good use of the DDR2 bandwidth that was available with the chipset memory controller.

Since last May/June DDR2 has finally turned the market, and it has made some remarkable transformations along the way. The early 5-5-5 timings at the official DDR2-800 speed have since been replaced by several high performance memories capable of 3-3-3 timings at DDR2-800. The best memory at DDR2-1066 can now operate at 4-4-3 timings, and the fastest DDR2 is now around DDR2-1266 and still getting faster.

Perhaps even more remarkable, in the last year DDR2 memory prices have dropped to half of what they once were (sometimes more), and today DDR2 is often cheaper than the DDR memory it replaced. Compared to the very expensive prices at launch and into the holiday buying season we see DDR2 is now the memory price standard in the desktop computer memory market.


>> Measuring RAM Speed <<

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 2003  Computer Memory Upgrade