Wikipedia
A DIMM or dual in-line memory module comprises a series of dynamic random-access memory integrated circuits These modules are mounted on a printed circuit board and designed for use in personal computers, workstations and servers DIMMs began to replace SIMMs (single in-line memory modules) as the predominant type of memory module as Intel P5-based Pentium processors began to gain market share While the contacts on SIMMs on both sides are redundant, DIMMs have separate electrical contacts on each side of the module Another difference is that standard SIMMs have a 32-bit data path, while standard DIMMs have a 64-bit data path
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