RAM Types

 It is a possible to identify several types of RAM when categorizing by their technology. These are:

Static RAM (SRAM)

This RAM will maintain its data as long as power is supplied to the memory chips. It does not want to be re-written periodically. SRAM is very faster than DRAM and very expensive than DRAM. SRAM is frequently used as cache memory proper to its speed. Each clock pulse generates out puts then and there no Refresh is needed because transistors are used for the Technology and has a faster switching.

Dynamic RAM (DRAM)

DRAM is not like a SRAM, must be frequently re-written (refreshing) as data maintaining is its main function. This type of Ram made and placing the memory on a refresh circuit that rewrites the data several hundred times/second. DRAM is used for most system memory (RAM) because it is less expensive.

Once a clock pulse is generated and the other pulse will be generated or accepted. After a Refresh because micro capacitor technology is used and these capacitors needs a charge and a discharge to accept the other pulse.

There are many types of DRAM

Fast Page Mode DRAM (FPM DRAM)

FPM DRAM is one and only slightly faster than regular DRAM. It uses a slightly efficient method of calling data from the memory. FPM DRAM is not used anymore due to its slow speed, but it is almost universally supported.

Speed 60 ns up to 80 ns (now a day’s not in use)

Bus width (Bit rate)

8 bit – 30 pin SIMM

16 bit/32 bit – 72 pin SIMM

64 bit – 168 pin DIMM

Extended Data out DRAM (EDO DRAM)

EDO DRAM is types of random access memory chip that improves the time of read time. It allows beginning while another is being completed. While this might sound ingenious; the performance increase over FPM DRAM is only slight. EDO DRAM must be properly supported by the chipset, but it is the most common type of memory for most users. Power users with high bus speeds typically opt for something faster, though.

Speed 50 ns up to 70 ns

16 bit/ 32 bit – 72 pin SIMM (Single Inline Memory Module)

64 bit – 168 pin DIMM (Dual Inline Memory Module)

Synchronous DRAM (SDRAM)

SDRAM has developed new standard for PC memory. Its speed is synchronous, meaning it is directly rely on the clock speed of the whole system. It works at the same as the system bus, up to 133 MHz Although SDRAM is faster, the speed is un-noticed by many users due to the fact that the system cache masked it. Also, most users are working on a relatively slow 66 MHz bus speed, which doesn’t use the SDRAM to its full capacity.

Speed 66 MHz up to 100 MHz – 133 MHz

64 bit- 168 pin DIMM

Each individual clock pulse generates an individual single output.

One clock pulse generates one instruction output then and there.

RAMBUS DRAM (RDRAM)

This is a technology still being developed by Intel that may prove to surpass SDRAM. Its goal is to get rid of the latency, the time taken to access memory. I do this by actually narrowing the bus path and treating the memory bus as a separate communication channel.

Speed 400 MHz up to 1200 MHz

16 bit – 184 pin RIMM – Rambus Inline Memory Module

DDR SDRAM – Double Data Rate SDRAM

64 bit- 184 pin DIMM

Speed 200 MHz upto 400 MHz

Each individual clock pulse generates a dual output

DDR2 SDRAM

Represented in new P4 supported motherboards.

64 bit – 240 pin DIMM

Speed 533 MHz  to 1066 MHz

DDR3 SDRAM

64 bit – 240 pin DIMM

Speed 1066 MHz to 1333 MHz