RAM Configurations—Discover how multi-channel memory layouts available on many systems can boost performance and how to install the modules. Currently there are two standards for these various DIMM types: DDR (Double Data Rate) and DDR2 (Double Data Rate2). The DDR2 is essentially an upgraded version of the DDR standard that allows for memory modules with lower power consumption, greater heat dissipation, increased speed capabilities, larger memory capacities, and increased performance. DDR2 SDRAM SPECIFICATION" (PDF). JESD79-2E. JEDEC. April 2008: 78 . Retrieved 2009-03-14. {{ cite journal}}: Cite journal requires |journal= ( help) Double data rate 2 SDRAM (DDR2 SDRAM) is the successor to DDR SDRAM. DDR2 SDRAM runs its external data bus at twice the speed of DDR SDRAM and features a four-bit prefetch buffer, enabling faster performance. However, DDR2 SDRAM memory has greater latency than DDR SDRAM memory. Latency is a measure of how long it takes to receive information from memory; the higher the number, the greater the latency. Typical latency values for mainstream DDR2 memory are CL=5 and CL=6, compared to CL=2.5 and CL=3 for DDR memory. 240-pin memory modules use DDR2 SDRAM. Ever-increasing amounts of RAM are needed as operating systems and applications get more powerful and add more features. Because RAM is one of the most popular upgrades to add to any laptop or desktop system during its lifespan, you need to understand how RAM works, which types of RAM exist, and how to add it to provide the biggest performance boost to the systems you maintain.

In this article, we are going to talk about the different form factors of RAM modules and how they are distinct from one another. RAM Form Factors DIMM Like desktop DIMMs, SODIMMs have also increased the number of pins over time. SDR SODIMMs had 144 pins, while DDR and DDR2 used 200 pins. DDR3 upped the pin count to 204, while DDR4 increased that to 260 and DDR5 to 262. This further ensures electrical incompatibility between generations of SODIMM memory. Where Are SODIMMs Used? Single-Sided vs Double-Sided—Learn what these terms mean and how they might affect how much RAM you can install on a particular system. Smith, Ryan (2020-07-14). "DDR5 Memory Specification Released: Setting the Stage for DDR5-6400 And Beyond". AnandTech . Retrieved 2020-07-15.

One of the most significant issues with small form factor computers, especially laptops, is thermal constraints. It can be difficult to dissipate heat from such a small area, especially with the limited airflow. To make it even worse for SODIMM memory. Laptops typically only allocate the required space, meaning there’s no room for a large heat sink like you find on full-size DIMMs. Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing. Memory module form factor (240-pin DIMM, 184-pin DIMM, 168-pin DIMM, 204-pin SO-DIMM, and so on)—The form factor your system can use has a great deal to do with the memory upgrade options you have with any given system. Although a few systems can use more than one memory module form factor, in most cases if you want to change to a faster type of memory module, such as from 184-pin DIMM (used by DDR SDRAM) to 240-pin DIMM (such as DDR2 or DDR3 SDRAM), you need to upgrade the motherboard first. JEDEC Standard No. 21C: 4.20.13 240-Pin PC2-5300/PC2-6400 DDR2 SDRAM Unbuffered DIMM Design Specification" **

Before working with any memory modules, turn the computer off and unplug it from the AC outlet. Be sure to employ electrostatic discharge (ESD) protection in the form of an ESD strap and ESD mat. Use an antistatic bag to hold the memory modules while you are not working with them. Before actually handling any components, touch an unpainted portion of the case chassis in a further effort to ground yourself. Try not to touch any of the chips, connectors, or circuitry of the memory module; hold them from the sides.DDR4 SODIMM: The latest iteration, providing further improvements in data rate and power efficiency over DDR3 SODIMMs. Double data rate 3 SDRAM (DDR3 SDRAM) Compared to DDR2, DDR3 runs at lower voltages, has twice the internal banks, and most versions run at faster speeds than DDR2. DDR3 also has an eight-bit prefetch bus. As with DDR2 versus DDR, DDR3 has greater latency than DDR2. Typical latency values for mainstream DDR3 memory are CL7 or CL9, compared to CL5 or CL6 for DDR2. Although DDR3 modules also use 240 pins, their layout and keying are different than DDR2, and they cannot be interchanged. MicroDIMMs have only been iterated to DDR2. These are even smaller than SODIMMs and primarily used in printers and other non-memory-invasive devices.

Most types of desktop memory modules use unbuffered memory. However, many servers and some desktop or workstation computers use a type of memory module called registered memory or buffered memory: buffered memory is the term used by the 220-901 exam. Buffered (registered) memory modules contain a register chip that enables the system to remain stable with large amounts of memory installed. The register chip acts as a buffer, which slightly slows down memory access. SPECIALITY DDR2-1066 SDRAM" (PDF). JEDEC. November 2007: 70 . Retrieved 2009-03-14. {{ cite journal}}: Cite journal requires |journal= ( help)

Memory is not compatible across all motherboards

https://www.google.com/books/edition/The_X86_Microprocessors_Architecture_And/zWrZY1OgTPsC?hl=en&gbpv=1&dq=dimm+simm+ram&pg=PA576&printsec=frontcover This all makes it harder to cool the RAM. This hasn’t been a massive issue in the p. Still, thermal management will get more complex as RAM speeds increase and the power management moves onto the SODIMM with DDR5. This will likely mean SODIMMs working on the lower end of the JEDEC standardized speeds. However, most use cases will see only a minimal difference with RAM speed changes. DIMMs are the memory modules you see inside desktop computers. They are relatively larger in size than the SODIMM and MicroDIMM modules. These are 133.35 mm (5.25 inches) in length.