Lesson 3.3 System Memory

Question 1

System RAM and Virtual Memory

Answer 1

• Address Space

Question 2

Address Space

Answer 2

Data Pathway
Address Pathway

Question 3

Data pathway

Answer 3

Determines the amount of information transferred per clock cycle. In a single channel memory controller, this bus is typically 64 bits wide.

Question 4

Address Pathway

Answer 4

Determines the number of memory locations the CPU can track, thus limiting the maximum physical and virtual memory.

Question 5

RAM Types

Answer 5

DRAM
SDRAM
DDR SDRAM
CAS latency

Question 6

Dynamic RAM (DRAM)

Answer 6

stores data bits as electrical charges in bit cells made of capacitors, that hold a charge, and transistors, that read the capacitor’s contents. A charged capacitor represents 1, non-charged represents 0.

Question 7

Synchronous DRAM (SDRAM)

Answer 7

is synchronized to the system clock, ensuring that memory operations are timed with the CPU’s instructions.

Question 8

Double Data rate SDRAM ( DDR SDRAM)

Answer 8

• doubles data transfer by transmitting data on both the rising and falling edges of the clock cycle.
• Double data rated (DDR) Series of high-bandwidth system-memory standards (DDR3/DDR4/DDR5) where data is transferred twice per clock cycle.

Question 9

DDR1 , Data rate, transfer rate, maximum size

Answer 9

• 200 to 400 MT/s
• 1.6 to 3.2 GB/s
• 1 GB

Question 10

DDR2 , Data rate, transfer rate, maximum size

Answer 10

• 400 to 1066 MT/z
• 3.2 to 8.5 GB/s
• 4 GB

Question 11

DDR3 , Data rate, transfer rate, maximum size

Answer 11

• 800 to 2133 MT/s
• 6.4 to 17.066 GB/S
• 16 GB

Question 12

DDR4 , Data rate, transfer rate, maximum size

Answer 12

• 1600 to 3200 MT/s
• 12.8 to 25.6 GB/s
• 32 GB

Question 13

DDR5 , Data rate, transfer rate, maximum size

Answer 13

• 4800 up to 8000+
• 38.4 to 51.3+ GB/s
• 128 GB or higher

Question 14

Clock Speed

Answer 14

Both the internal memory device clock speed and the memory bus speed are 100 MHz.

Question 15

Data Rate

Answer 15

DDR performs two operations per clock cycle, resulting in a data rate of 200 megatransfers per second (MT/s), hence the DDR-200 designation.

Question 16

Peak Transfer Rate

Answer 16

The peak transfer rate is 1600 MBps (200 MT/s multiplied by 8 bytes per transfer), giving the PC-1600 designation. This is equivalent to 1.6 GBps.

Question 17

Memory Modules

Answer 17

• DIMM ( Dual Inline Memory Module (DIMM) )
• SODIMM ( Small Outline DIMMS) - laptops
• Installation
• Incompatibility
  
  • DDR4 module will not fit DDR3 slots

Question 18

Muti-Channel System Memory

Answer 18

• Single-channel
• Dual-channel
• Slot arrangement, installation, setup
• Mismatched module
• Triple/quadruple-channel

Question 19

Single-Channel

Answer 19

• System-memory controller configuration that provides one data pathway between the memory modules and the CPU.
• Features one 64-bit data bus between the CPU, memory controller, and RAM, which can limit data transfer rates.

Question 20

Dual-channel

Answer 20

• Utilizes two 64-bit pathways, allowing 128 bits of data per transfer, effectively doubling the data bandwidth. This requires support from the CPU, memory controller, and motherboard, but not from the RAM modules themselves. Ordinary RAM modules are used; there are no specific “dual-channel” DDR memory modules.
• System-memory controller configuration that provides two data pathways between the memory modules and a compatible CPU.

Question 21

Installation

Answer 21

To enable dual-channel, install identical modules in the corresponding slots of each channel (e.g., A1 and B1). The modules should match in clock speed, capacity, timings, and latency. Clock speed refers to the frequency at which the memory operates, affecting how quickly data can be processed. Timings and latency refer to the delay before data transfer begins, with lower values indicating faster performance. If the modules do not match, the system will default to the lowest (worst performing) values.

Question 22

Slot Arrangement

Answer 22

Dual-channel motherboards often have four DIMM slots arranged in color-coded pairs. Each pair represents one channel (e.g., channel A might be orange, and channel B might be blue).

Question 23

System Setup

Answer 23

Dual-channel mode may need to be enabled via the PC firmware’s system setup program.

Question 24

Triple-channel

Answer 24

System-memory controller configuration that provides three data pathways between the memory modules and a compatible CPU.

Question 25

Quadruple-channel

Answer 25

System-memory controller configuration that provides four data pathways between the memory modules and a compatible CPU.