3.2 - An Overview of Memory

Question 1

What is memory?

Answer 1

• Random Access Memory (RAM)is the most common
  – But it’s not the only kind of memory
• RAM is not referring to hard drive or SSD storage
  – Don’t mix the two terms
  – Data is stored permanently on the drive
• Data and programs can only be used when moved to RAM

Question 2

RAM (Random Access Memory) slots

Answer 2

• Memory types have changed through the years
  – Driven by standardization and technology
• One of the most important components of your computer
  – Speed, speed, speed
• Every motherboard is different
  – Check your documentation

Question 3

DIMM

Answer 3

• DIMM - Dual inline memory module
  – Electrical contacts are different on each side
• 64 bit data width

Question 4

SO-DIMM

Answer 4

• Small Outline Dual In-line Memory Module
  – About half the width as a DIMM
• Used in laptops and mobile devices

Question 5

Dynamic Random Access Memory (DRAM)

Answer 5

• The memory on the DIMM
• Dynamic
  – Needs constant refreshing
  – Without refreshing, the data in memory disappears
• Random access
  – Any storage location can be accessed directly
  – Unlike magnetic tape

Question 6

SDRAM

Answer 6

• Synchronous DRAM (SDRAM)
• SDRAM is synchronous with the common system clock
  – Queue up one process while waiting for another
  – Classic DRAM didn’t wait for a clock signal

Question 7

Double Data Rate 3 (DDR3) SDRAM

Answer 7

• Twice the data rate of DDR2
  – Larger chip capacities - Maximum 16 GB per DIMM
• No backwards compatibility
  – Speed brings sacrifice

Question 8

Double Data Rate 4 (DDR4) SDRAM

Answer 8

• Speed increases over DDR3
  – Faster frequencies
  – Maximum 64 GB per DIMM
• Again, no backwards compatibility

Question 9

Double Data Rate 5 (DDR5) SDRAM

Answer 9

• Faster data transfers between the memory module and
  motherboard
  – Maximum of 64 GB per DIMM
• The key has moved - No backwards compatibility

Question 10

SDR vs. DDR

Answer 10