RANDOM ACCESS MEMORY (RAM)

RANDOM ACCESS MEMORY (RAM)

      “A computer uses RAM to hold volatile (temporary) instructions and data needed for processing”.

MEMORY MODULES       

·        SIMM

·        DIMM )SD, DDR, DDR2, DDR3)

·        RIMM

SIMM (Single Inline Memory Module)

• 6-9 memory chips on the circuit board.
• The contacts on the SIMM are same on both sides.
• Using in pair & used in older pc’s.

DIMM (Dual Inline Memory module)

• DIMMs are 64bit data path.
• The contacts on the DIMM are different on both sides.
• Command addresses & control singles are buffered.

RIMM (Ram bus Inline Memory Module)

·        ECC supported.

·        Requires continuous singles.

·        Must use C-RIMMs (Continuity RIMM) to empty slots.

·        Faster

·        1600 Mb/s bandwidth.

DIMMs (Dual Inline Memory Module)

SDRAM

• Synchronous Dynamic Random Access Memory.
• Waits for clock single before responding to its control inputs.

DDR RAM

• Double Data Rate Random Access Memory.
• Doubling the speed of the memory.

DDR2 RAM

• Double Data Rate 2 Random Access Memory.
• Second generation of DDR.
• Capable of operating at greater speeds storage.
• Greater bandwidth.
• Low power consumption (1.8v) & less heat.
• Incompatible with DDR slots.

DDR3 RAM

• Double Data Rate 3 SD Random Access Memory.
• Third generation of DDR.
• Capable of operating at greater speeds storage.
• Greater bandwidth (1600Mb/s).
• Low power consumption (1.5v) & less heat (thermal design).

• Incompatible with DDR slots

RAM Technologies

Static RAM (SRAM): This RAM will maintain its data as long as power is provided to the memory chips. It does not need to be rewritten periodically. SRAM is very fast but very expensive than (DRAM). SRMA is often used as cache memory due to its speed.

Dynamic RAM (DRAM): Unlike SRAM, must be continually re-written (refreshing) in order for it to maintain its data.

This is done by placing the memory on a refresh circuit that rewrites the data several hundred times pre second. DRAM is used for most system memory (RAM) because it is cheap.