RAM

Random Access Memory stores frequently used program instructions in order for software to function. RAM is installed on the motherboard in memory slots and are called DIMM's or Dual Inline Memory Modules. A motherboard generally have 2 to 4 DIMM memory slots.

Dual Inline Memory Modules contain either 168, 184, 240 or 288 pins at the bottom of the module. DIMM's require constant power to store data. RAM contains multiplexing and demultiplexing circuitry designed to connect the data line to the addressed storage for reading or writing. RAM devices often have multiple data line and are said to be 8 bit or 16 bit devices. RAM is normally associated with Volatile types of memory like DRAM (Dynamic Random Access Memory) and when the power is stopped the information is lost.

Types Of RAM

DDR - Double Data Rate RAM, sends double the amount of data utilizing both the rising and falling edge in a clock cycle compared to other non-DDR RAM. DDR RAM may include both the clock speed and total bandwidth on the module.

DDR2 - Has 240 pins and is faster than DDR as it allows for higher bus speeds and sends twice the amount of data at a lesser power consumption rate.

DDR3 - Also has 240 pins, the bottom notches are in a different positions and is also faster with less power consumption.

DDR4 - This module has 288 pins, offers higher speed transfers and again uses less power then DDR3

ECC - Error Correcting Code detects if data was correctly process and makes a correction where needed. 

Other,

SRAMBSRAMFPM DRAM
EDRAMEDO DRAMBEDO DRAM
NVRAMSDRAMESDRAM
JEDEC SDRAMPC-100 SDRAMDRDRAM
SLDRAMFRAMVRAM
GDDR RAMRAMDACSGRAM
WRAMMDRAMRDRAM

Type of Memory Modules

DIMM - transfers 64 bits of data in 1 clock cycle which has a 8 byte wide bus.

SIMM - transfers 32 bits of data in 1 clock cycle which has a 4 byte wide bus.

RIMM - Rambus Inline Memory Module, RIMM have 184 pins and look similar to a DIMM except the bottom notches are in the centre of the module.

SODIMM - Small Outline Dynamic Inline Memory Module, Are 32 bits and are used in laptops and notebook computers.

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