DDR memory is a type of RAM that allows for increased performance over single data rate memory by facilitating two data transactions per clock cycle without doubling the clock speed. It consists of over 130 signals and uses mode and extended mode registers to control operations. DDR memory comes in SRAM and DRAM varieties, with DRAM being more common due to its lower power consumption and use in main memory, though it requires constant refreshing to prevent data loss.

1. DDR Memory

2. Memory (Basic)
• Collection of storage cells together
• Involves circuit to transfer information across
• Different device has different memory
architecture

4. RAM/ Random Access Memory
• Volatile memory(information is lost when
power supply OFF)
• When open program, it load it to RAM from
hard disk.
• Consist of multiplexing and demultiplexing
circuit to make data to provided address

5. BLOCK DIAGRAM OF RAM

6. TYPES OF RAM
• SRAM( Static random access memory): Holds
data in static form
• DRAM( Dynamic Random access memory): It
constantly needs to be refreshed and lose
data shortly

7. DRAM FEATURES
• Less power consumption
• Used in main memory
• Needs more memory and needs to be
refreshed constantly.

8. DDR SDRAM
• It is Double Data Rate system
• Increased performance over Single Data Rate.
• Two data transactions occur without doubling the
applied clock
• DDR memory consist of more than 130 signals.

9. DDR SDRAM REGISTERS
• MODE REGISTER: The mode register is used to
define the mode of operation of ddr sdram
• EXTENDED MODE REGISTER: It controls the
operations that are beyond mode registers

10. Commands of DDR SDRAM
• DESELECT
• NO OPERATION
• ACTIVE
• READ
• WRITE
• BURST TERMINATE
• PRE CHARGE
• AUTO refresh

11. ADVANTAGES OF DDR SDRAM
• Comparable Bandwidth level
• Lower latency cost

12. DISADVANTAGES OF DDR SDRAM
• Poor bus efficiency 65%
• Not by Intel

13. COMPARISION

14. DDR4 SDRAM
• Greater bandwidth
• Power Savings
• Performance enhancement

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