RAM types Dynamic RAM (DRAM) Static RAM (SRAM)

2. Outline
• Introduction .
• RAM types .
• DRAM .
• SRAM .

3. Introduction
RAM “Random Access Memory” is a form of
data storage that can be accessed randomly at
any time, in any order and from any physical
location., allowing quick access.
RAM is volatile i.e. its contents are lost when
the device is powered off.
RAM allows the computer to read data quickly
to run applications. It allows reading and
writing.

4. RAM types
The two main types of RAM are static
RAM and dynamic RAM.
Static RAM (SRAM)
 4 times more expensive
 Very low access time .
 Information stored on
RS flip-flops .
 No need for refreshing .
 They made of transistors
 it is used in cache .
 They can be either
Bipolar or MOS
technology .
Dynamic RAM (DRAM)
 Low cost .
 Consumes less power .
 Information stored on
FET transistors .
 Needs to be refreshed .
 These are mostly made
of capacitors .
 it is used in main
memory
 These are available
only in MOS technology

5. RAM types

6. FPM RAM
• Fast Page Mode Dynamic Random Access Memory
It was the original form of DRAM. It waits through the entire
process of locating a bit of data by column and row and then
reading the bit before it starts on the next bit. Maximum
transfer rate to L2 cache is approximately 176 Mbps.

7. EDO RAM
• Extended data-out Dynamic Random Access Memory
does not wait for all of the processing of the first bit before
continuing to the next one. As soon as the address of the first
bit is located, EDO DRAM begins looking for the next bit. It is
about five percent faster than FPM. Maximum transfer rate to
L2 cache is approximately 264 Mbps.

8. SDRAM
• Synchronous DRAM .
• SDRAM is a type of dynamic random access memory which is
synchronized with the clock speed that the microprocessor is
optimized for. SDRAM is about five percent faster than EDO
RAM and is the most common form in desktops today. Maximum
transfer rate to L2 cache is approximately 528 Mbps.

9. DDR RAM
• Double data rate synchronous dynamic RAM is just like
SDRAM except that is has higher bandwidth, meaning greater
speed. It is a newer variant of SDRAM. Maximum transfer rate
to L2 cache is approximately 1,064 Mbps .

10. DDR2 RAM
• Double Data Rate 2 .
• newer version of DDR .
• twice as fast as the original DDR RAM.
• 2003 .
• still is double data rate just like the original DDR.
• DDR2-RAM has modified signaling which enables higher
speeds to be achieved with more immunity to signal noise
and cross-talk between signals .

13. RDRAM
• Rambus dynamic random access memory : Designed by
Rambus, RDRAM uses a Rambus in-line memory module
(RIMM), which is similar in size and pin configuration to a
standard DIMM. RDRAM memory chips work in parallel to
achieve a data rate of 800 MHz, or 1,600 Mbps. Since they
operate at such high speeds, they generate much more heat
than other types of chips .

17. REFERANCE
• http://www.diffen.com/difference/RAM_vs_ROM
• http://en.wikipedia.org/wiki/Random_access_memory
• https://www.google.ps/search?tbm=isch&q=compare+bet
ween+type+of+DRAM+&ei=Lxk0VaDUB4HasgH0qISoBg#imgrc
=_
• MEMORY : RAM AND ITS USES – SHARDA UNIVERSITY - School
of Engineering & technology - DIGITAL ELECTRONICS – I
• Computer Organization and Architecture Designing for
Performance (8th Edition)