Specifications
Computer Architecture and Maintenance (G-Scheme-2014)
ODT : On-die termination (ODT) is the technology where the termination resistor
for impedance matching in transmission lines is located inside a semiconductor chip
instead of on a printed circuit board.
Types of Memory
Types of RAM in computer system
The following are some common types of RAM:
• SRAM: Static random access memory uses multiple transistors, typically four to
six, for each memory cell but doesn't have a capacitor in each cell. It is used
primarily for cache.
• DRAM: Dynamic random access memory has memory cells with a paired
transistor and capacitor requiring constant refreshing.
• FPM DRAM: Fast page mode dynamic random access memory 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.
• EDO DRAM: 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.
• SDRAM: Synchronous dynamic random access memory takes advantage of the
burst mode concept to greatly improve performance. It does this by staying on
the row containing the requested bit and moving rapidly through the columns,
reading each bit as it goes. The idea is that most of the time the data needed by
the CPU will be in sequence. 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.
• DDR SDRAM: Double data rate synchronous dynamic RAM is just like
SDRAM except that is has higher bandwidth, meaning greater speed. Maximum
transfer rate to L2 cache is approximately 1,064 MBps (for DDR SDRAM 133
MHZ).
• RDRAM: Rambus dynamic random access memory is a radical departure from
the previous DRAM architecture. Designed by Rambus, RDRAM uses a Rambus
Prepared By – Prof. Manoj.kavedia (9860174297 – 9324258878 ) (www.kavediasir.yolasite.com)
80