CPU- Purpose
• To run program code
• To manipulate data
• The CPU is the “brain†of a computer
CPU- Manufacturers
• There are two main manufacturers of CPU “chips†or Integrated
Circuits (ICs)
– Intel
– AMD (Advanced Micro Devices)
Architecture
• The physical structure of the CPU
– Control Unit
– ALU- Arithmetic Logic Unit
– FPU- Floating Point Unit
– Data I/O Bus
– Address Bus
– Internal Data Bus (Internal Registers)
– Cache (L1, L2, L3)
Control Unit
• Decodes instructions from the currently running program
• These instructions control the actions of the:
– ALU
– FPU
Arithmetic Logic Unit / Floating Point Unit
• ALU- Arithmetic Logic Unit
– Primary processing component of CPU
– Processes data moving it back and forth between the registers as it is manipulated
• FPU- Floating Point Unit
– Performs more complex calculations than the ALU can
Data (I/O) Bus
• aka Processor bus, frontside bus, processor-side bus
• The pathway used to move data between the CPU, RAM and
chipset (Northbridge or MCH)
• Typically 64 bits wide
• Speed measured in MHz
• The wider and faster the bus the better
Address Bus
• Carries the addressing information that the CPU uses to access data in RAM (Random Access Memory)
• The wider the bus the more memory that can be accessed
Internal Data Bus
• aka (Internal) Registers
• Temporary internal storage
• Identifies:
– How much data the CPU can operate on per clock cycle
– How data is moved around the CPU internally
• Bus widths:
– 32 bits wide (≤80486)
• Allows 32-bit OS and applications to be run
– 32 or 64 bits wide (≥Pentium and AMD K5)
• Allows 32-or 64-bit OS and applications to be run
Cache Memory
• High speed memory placed between the processor and RAM
• Temporarily stores data that the processor needs
• Provides faster access to this data than if it was accessed directly from RAM
• Is a form of intelligent buffer
– An algorithm tries to predict what data is required next
• Built into the CPU die (ie part of the CPU core)
• Runs at the speed of the CPU
• All CPUs support L1 and L2 cache
• Some CPUs support L3 cache
• L1- Level 1
– Closest to the CPU
– Typical size: 32KB
• L2- Level 2
– Slightly further away from the CPU
– Connected to the CPU via the backside bus
– Typical size: 2MB
• L3- Level 3
– Only found on some server processors
– Larger size L2 cache usually replaces L3
CPU Modes
• Real Mode
– Runs 16-bit software
• IA-32 Mode (IA- Intel Architecture)
– Protected Mode (Runs 32-bit software)
– Virtual Real Mode/V86 Mode (Runs 16-bit software in a 32-bit environment)
• IA-32e 64-bit Extension Mode (64bit CPUs only)
– 64-bit Mode (Runs 64-bit software)
– Compatibility Mode (Runs 32-bit software in a 64-bit environment)
CPU Technologies
• The features of the CPU
– Speed
– Multiplier/Overclocking/Throttling
– Pipelining
– Hyperthreading
– Dual/Quad Core
– Micro Code (MMX)
– Voltage Regulator Module (VRM)
Speed
• How fast the CPU operates
• Based on the oscillations of a crystal, typically, contained in the
chipset
• Measured in millions or billions of cycles per second (MHz or GHz)
• Due to the differences in internal archi-tecture between processors/manufacturers
• Comparing raw speeds of different processors is not always a good indication of which processor is the faster of two, ie multiple instructions per clock cycle
• AMD rates it's processor speeds in relation to Intel even though the actual speed may be slower
Multiplier
• The factor which matches the speed of the motherboard bus to the internal speed of the CPU
• Can be set automatically or from within BIOS
Overclocking
• Running a CPU at a speed faster than its rated speed
• Can provide better performance but with potentially reduced life
• Is setup via BIOS
• Increase clock speed incrementally
Throttling
• Slowing down the CPU to reduce:
– Power consumption
– Heat
– Noise from cooling fans
• Automatically controlled by the CPU
Pipelining
• aka Superscalar Technology
• A technique to speed up instruction execution
• Multiple instructions can be executed per clock cycle
Hyper Threading Technology
• HTT allows a single processor:
– To run two independent sets of instructions simultaneously
– To create two logical processors
• An OS with Symmetric Multi-processing (SMP) support sees these two logical processors as two separate processors
• Each HTT enabled processor has:
– Two sets of general purpose and control registers
– Shared cache, execution units and buses
• Each logical processor is able to process a single thread simultaneously
– Thread: a small part of a program that is being executed
• If one processor is idle, the other can use its unused resources
• HTT requires:
– A compatible chipset/BIOS
– A BIOS where HTT can be enabled or disabled depending on OS support for HTT
– An OS that supports HTT
• Not all applications support HTT and may run slower as a result
Multi-Core CPUs
• Dual Core
– Two processors (cores) built onto a single die
• Quad Core
– Four processors (cores) built onto a single die
• The cores share system resources, eg L2 cache
• Requires a single motherboard socket
• Theoretically:
– Do not require a Motherboard upgrade
• Practically:
– Might require a BIOS/Chipset upgrade
• No need to re-write applications to use multi-core as each core is seen as a separate processor
Multimedia Extensions MMX
• Introduced with the Pentium 2 (P2), giving:
– Improved video compression/decompression
– Image manipulation
– Encryption
– I/O processing
• MMX Architecture provided:
– Added 57 new commands to instruction set
– Single Instruction, Multiple Data SIMD
Voltage Regulator Module (VRM)
• Electronic circuit built into the motherboard
• Senses the processor operating voltage
• Provides that operating voltage to the processor
Cooling Systems
• The CPU needs to be cooled to keep it within its operating temperature range
• Cooling can be provided by:
– Passive heat sinks
– Active heat sinks
– Case mounted fans
Passive Heatsink
• A passive heatsink is an aluminium-finned radiator mounted on the
CPU chip
– It dissipates heat by convection
– The fins provide a greater surface area for more efficient cooling
– The heatsink may be clamped or screwed down
Active Heatsink
• An active heatsink is a passive heatsink with an additional cooling mechanism
– Air Cooling
• Cool air is forced over a CPU mounted heatsink by means of a fan mounted on the heatsink
– Liquid Cooling
• Heat is extracted from the CPU by liquid flowing through a water block attached to it
• A pump circulates the liquid through a radiator which cools it
Case Fans
• Case fans are extra cooling fans mounted within the PC case
– Are separate to the PSU fan
– Provide additional cooling
– Note:
• Ensure the PSU can power the extra fans
• Check the airflow direction of the fans before mounting
Thermal Compound
• Thermal Compound is a glue-like zinc-based paste placed between the processor and heatsink
– It aids the transfer of heat between processor and heat sink or water block
• To run program code
• To manipulate data
• The CPU is the “brain†of a computer
CPU- Manufacturers
• There are two main manufacturers of CPU “chips†or Integrated
Circuits (ICs)
– Intel
– AMD (Advanced Micro Devices)
Architecture
• The physical structure of the CPU
– Control Unit
– ALU- Arithmetic Logic Unit
– FPU- Floating Point Unit
– Data I/O Bus
– Address Bus
– Internal Data Bus (Internal Registers)
– Cache (L1, L2, L3)
Control Unit
• Decodes instructions from the currently running program
• These instructions control the actions of the:
– ALU
– FPU
Arithmetic Logic Unit / Floating Point Unit
• ALU- Arithmetic Logic Unit
– Primary processing component of CPU
– Processes data moving it back and forth between the registers as it is manipulated
• FPU- Floating Point Unit
– Performs more complex calculations than the ALU can
Data (I/O) Bus
• aka Processor bus, frontside bus, processor-side bus
• The pathway used to move data between the CPU, RAM and
chipset (Northbridge or MCH)
• Typically 64 bits wide
• Speed measured in MHz
• The wider and faster the bus the better
Address Bus
• Carries the addressing information that the CPU uses to access data in RAM (Random Access Memory)
• The wider the bus the more memory that can be accessed
Internal Data Bus
• aka (Internal) Registers
• Temporary internal storage
• Identifies:
– How much data the CPU can operate on per clock cycle
– How data is moved around the CPU internally
• Bus widths:
– 32 bits wide (≤80486)
• Allows 32-bit OS and applications to be run
– 32 or 64 bits wide (≥Pentium and AMD K5)
• Allows 32-or 64-bit OS and applications to be run
Cache Memory
• High speed memory placed between the processor and RAM
• Temporarily stores data that the processor needs
• Provides faster access to this data than if it was accessed directly from RAM
• Is a form of intelligent buffer
– An algorithm tries to predict what data is required next
• Built into the CPU die (ie part of the CPU core)
• Runs at the speed of the CPU
• All CPUs support L1 and L2 cache
• Some CPUs support L3 cache
• L1- Level 1
– Closest to the CPU
– Typical size: 32KB
• L2- Level 2
– Slightly further away from the CPU
– Connected to the CPU via the backside bus
– Typical size: 2MB
• L3- Level 3
– Only found on some server processors
– Larger size L2 cache usually replaces L3
CPU Modes
• Real Mode
– Runs 16-bit software
• IA-32 Mode (IA- Intel Architecture)
– Protected Mode (Runs 32-bit software)
– Virtual Real Mode/V86 Mode (Runs 16-bit software in a 32-bit environment)
• IA-32e 64-bit Extension Mode (64bit CPUs only)
– 64-bit Mode (Runs 64-bit software)
– Compatibility Mode (Runs 32-bit software in a 64-bit environment)
CPU Technologies
• The features of the CPU
– Speed
– Multiplier/Overclocking/Throttling
– Pipelining
– Hyperthreading
– Dual/Quad Core
– Micro Code (MMX)
– Voltage Regulator Module (VRM)
Speed
• How fast the CPU operates
• Based on the oscillations of a crystal, typically, contained in the
chipset
• Measured in millions or billions of cycles per second (MHz or GHz)
• Due to the differences in internal archi-tecture between processors/manufacturers
• Comparing raw speeds of different processors is not always a good indication of which processor is the faster of two, ie multiple instructions per clock cycle
• AMD rates it's processor speeds in relation to Intel even though the actual speed may be slower
Multiplier
• The factor which matches the speed of the motherboard bus to the internal speed of the CPU
• Can be set automatically or from within BIOS
Overclocking
• Running a CPU at a speed faster than its rated speed
• Can provide better performance but with potentially reduced life
• Is setup via BIOS
• Increase clock speed incrementally
Throttling
• Slowing down the CPU to reduce:
– Power consumption
– Heat
– Noise from cooling fans
• Automatically controlled by the CPU
Pipelining
• aka Superscalar Technology
• A technique to speed up instruction execution
• Multiple instructions can be executed per clock cycle
Hyper Threading Technology
• HTT allows a single processor:
– To run two independent sets of instructions simultaneously
– To create two logical processors
• An OS with Symmetric Multi-processing (SMP) support sees these two logical processors as two separate processors
• Each HTT enabled processor has:
– Two sets of general purpose and control registers
– Shared cache, execution units and buses
• Each logical processor is able to process a single thread simultaneously
– Thread: a small part of a program that is being executed
• If one processor is idle, the other can use its unused resources
• HTT requires:
– A compatible chipset/BIOS
– A BIOS where HTT can be enabled or disabled depending on OS support for HTT
– An OS that supports HTT
• Not all applications support HTT and may run slower as a result
Multi-Core CPUs
• Dual Core
– Two processors (cores) built onto a single die
• Quad Core
– Four processors (cores) built onto a single die
• The cores share system resources, eg L2 cache
• Requires a single motherboard socket
• Theoretically:
– Do not require a Motherboard upgrade
• Practically:
– Might require a BIOS/Chipset upgrade
• No need to re-write applications to use multi-core as each core is seen as a separate processor
Multimedia Extensions MMX
• Introduced with the Pentium 2 (P2), giving:
– Improved video compression/decompression
– Image manipulation
– Encryption
– I/O processing
• MMX Architecture provided:
– Added 57 new commands to instruction set
– Single Instruction, Multiple Data SIMD
Voltage Regulator Module (VRM)
• Electronic circuit built into the motherboard
• Senses the processor operating voltage
• Provides that operating voltage to the processor
Cooling Systems
• The CPU needs to be cooled to keep it within its operating temperature range
• Cooling can be provided by:
– Passive heat sinks
– Active heat sinks
– Case mounted fans
Passive Heatsink
• A passive heatsink is an aluminium-finned radiator mounted on the
CPU chip
– It dissipates heat by convection
– The fins provide a greater surface area for more efficient cooling
– The heatsink may be clamped or screwed down
Active Heatsink
• An active heatsink is a passive heatsink with an additional cooling mechanism
– Air Cooling
• Cool air is forced over a CPU mounted heatsink by means of a fan mounted on the heatsink
– Liquid Cooling
• Heat is extracted from the CPU by liquid flowing through a water block attached to it
• A pump circulates the liquid through a radiator which cools it
Case Fans
• Case fans are extra cooling fans mounted within the PC case
– Are separate to the PSU fan
– Provide additional cooling
– Note:
• Ensure the PSU can power the extra fans
• Check the airflow direction of the fans before mounting
Thermal Compound
• Thermal Compound is a glue-like zinc-based paste placed between the processor and heatsink
– It aids the transfer of heat between processor and heat sink or water block
