Specifications
Computer Architecture and Maintenance (G-Scheme-2014)
because of the extra logic features. But the benefits of SDRAM allowed more than one 
set of memory, which increased the bandwidth efficiency.
        With the introduction of DDR, SDRAM quickly began to fade out of use because 
DDR   was   cheaper   and 
more   cost  effective.   The 
SDRAM  used  a  168-pin 
while the DDR module 
used   a   184-pin.   SDRAM 
modules used a voltage of 
3.3V and DDR used 2.6V, 
producing less heat.
Features of SDRAM
1) Speed is between 100Mhz to 133Mhz
2) Sizes Available is 32Mb,64Mb,128Mb,256Mb,512Mb,1Gb
3) Operating Voltage is 3.3V
4) Synchronous Architecture
5) SDRAM is synchronized with the computer's clock to allow it to send 
instructions more efficiently by joining a pipeline of other instructions the 
computer is processing. 
6) The pipelining of information in a computer allows it to receive another 
command before it has finished processing the previous command. 
7) This allows SDRAM to operate at much higher speeds, making it the most 
popular form of RAM offered on computers.
8) SDRAM module are of 168 pin
9) It prefetch 1 bit at a time
 DDR (Dual Data Rate)
Q.What is DDR
Ans.  In computing, a computer bus operating with double data rate (DDR) transfers 
data on both the rising and falling edges of the clock signal.This is also known as 
double pumped, dual-pumped, and double transition. The term toggle mode is used in 
the context of NAND flash memory.
The simplest  way  to design  a clocked   electronic   circuit is to   make it   perform   one 
transfer per full cycle (rise and fall) of a clock signal. This, however, requires that the 
Prepared By – Prof. Manoj.kavedia (9860174297 – 9324258878 ) (www.kavediasir.yolasite.com)
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