240pin

240-pin is a descriptor for desktop memory modules that use 240 edge contacts, commonly associated with DDR2 and DDR3 SDRAM DIMMs. The term denotes the pin count of the module’s edge connector, but it does not specify a single standard; the two main generations that use 240 pins (DDR2 and DDR3) are not interchangeable due to different notch positions and electrical specifications.

DDR2 and DDR3 memory both employ 240-pin DIMMs, typically with 120 contacts on each side of the module. Despite the same pin count, the physical keying (notch location) and the signaling requirements differ, so a DDR2 DIMM usually does not fit a DDR3 slot, and vice versa. In desktops, these modules are used with motherboards and CPUs that implement the corresponding memory controller, and compatibility is ensured by the motherboard’s supported memory generation.

Voltage, speed, and density distinguish DDR2 from DDR3. DDR2 DIMMs generally operate around 1.8V (with variations), while DDR3 DIMMs typically use 1.5V, including low-voltage variants. Both generations offer ECC (error-correcting) and non-ECC variants, and both have unbuffered forms common in desktops; registered/buffered memory is more typical in servers.

Historical context and current usage: 240-pin DDR2 DIMMs were widely used in desktops in the mid- to late-2000s, followed by DDR3 DIMMs in the late 2000s through the 2010s. DDR4, which uses 288 pins, largely supplanted DDR3 in newer systems. Today, 240-pin DIMMs are mainly found in older or legacy systems or in contexts requiring compatibility with DDR2/DDR3 platforms, rather than in modern builds.

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