The Difference Between Notebook and Desktop Memory

Desktop PC Memory (DIMM)

 

                   There are a large number of RAM types available for desktop computer systems. The most commonly used types today are DIMMs (Dual In-Line Memory Module) and these are the small circuit boards that holds memory chips. DIMMs are standard in desktop computers, and common types of DIMMs include the following;

SDRAM- Synchronous Dynamic Random Access Memory
          Short for Synchronous DRAM, this is a type of DRAM that synchronizes itself with the CPU's bus. SDRAM, until recently, was the memory standard for modern PCs. When looking at SDRAM The number following "PC" indicates the speed of the system's front side bus. (example: The PC100 SDRAM is designed for systems equipped with a 100 MHz front side bus.)

DDR SDRAM- Double Data Rate Synchronous Dynamic Random Access Memory
            Short for Double Data Rate-Synchronous DRAM, a type of SDRAM that supports data transfers on both edges of each clock cycle (the rising and falling edges), effectively doubling the memory chip's data throughput. DDR-SDRAM also consumes less power, which makes it well-suited to notebook computers. DDR-SDRAM is also called SDRAM II. and DDRAM. DDR-SDRAM (and subsequent DD2 and DD3) as well as RDRAM are the technologies which are replacing SDRAM.

DDR2 SDRAM-Double Data Rate Two(2) Synchronous Dynamic Random Access Memory
                 DDR2 SDRAM is the next step up from DDR SDRAM. DDR2 SDRAM offers new features and functions that enable higher clock and data rate operations. DDR2 transfers 64 bits of data twice every clock cycle. DDR2 SDRAM memory is not compatible with current DDR SDRAM memory slots.

DDR3-SDRAM - Double Data Rate Three(3) Synchronous Dynamic Random Access Memory
            The third generation of DDR-SDRAM that improves upon DDr2-SDRAM by offering reduced power consumption, a doubled pre-fetch buffer, and also offers more bandwidth because of its increased clock rate.

You're SO DIMM - Notebook/Laptop Memory Is Different

              Something you may encounter is that there are more notebook(or laptop computer) manufacturers, who use proprietary memory modules. However, most commonly supported by notebook manufacturers is the SO DIMM (Small Outline DIMM), which is a smaller version of the DIMM modules that are used in desktops.

              What differentiates the notebook RAM from desktop RAM is its form factor; that is, its physical size and its pin configuration. A full-size DIMM has 100, 168, 184, or 240 pins and is usually 4.5 to five inches in length. In contrast, a SO DIMM has 72, 100, 144, or 200 pins and is smaller - 2.5 to 3 inches. There is also SO RIMM, which is similar to SO DIMM, but like DIMM/RIMM, it uses Rambus, Inc. technology and also has a different pin count.

Webopedia Memory Category
Webopedia's terms listings and information about computer memory.

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