Static vs Dynamic RAM

Question 1

Static RAM (SRAM)

Answer 1

Faster & more reliable than DRAM…why?

SRAM doesn’t need refreshed like DRAM and works as long as power is supplied to the circuit

SRAM uses transistors (6t)…SRAM does not use capacitors. Other types of SRAM can use 4t, 8t or 10t,

A typical SRAM cell is made up of sixMOSFETs. This storage cell has two stable states which are used to denote 0 and 1.

Two additional access transistors serve to control the access to a storage cell during read and write operations.

If the power is turned off or lost temporarily, SRAM contents will be lost

Question 2

SRAM Cont.

Answer 2

SRAM devices offer extremely fast access times (several times faster than DRAM)

Because SRAM is faster (SRAM uses transistors) …its more expensive to produce than DRAM

SRAM is used mainly as CPU cache between CPU & main memory which helps to reduce access times from main memory

Typically, it is several megabytes in size

Question 3

Dynamic RAM

Answer 3

DRAM, on the other hand, has an extremely short data lifetime-typically about four milliseconds.

This is true even when power is applied constantly.

Most common type of memory used today as it is cheap to make

Question 4

Dynamic RAM cont.

Answer 4

Most commonly, modern systems are “byte-accessible” which means that depending on the computer, each cell can hold 1 byte of information and is made up of 2 components.

Capacitors and Transistors

Capacitors (Are used to store information)

Transistors (Acts as a switch and lets control circuitry read the capacitor or change its state)

The memory (DRAM) controller periodically reads memory and writes it back again – refreshing data before it expires - takes time

Question 5

Another SRAM vs DRAM explanation

Answer 5

SRAM (Static RAM) retains it’s state so long as power keeps being applied.

DRAM (Dynamic RAM) does not retain it’s state unless it is periodically refreshed (read and the same value written back to tgat address).

SRAM is easier to work with and less power hungry than DRAM, but DRAM is much denser (how much memory can be packed into a given space) and much MUCH cheaper per MB.

Both are used in computers for different purposes. DRAM is what you likely think of as “RAM”, while SRAM is typically used for CPU cache memory.