1. Central Processing Unit- CPU

2. Introduction
The Central Processing Unit (Normally called a processor or CPU) is the brain of the PC. It executes instructions which enbles a computer to perform various tasks.
Some of the tasks include burning CDs or DVDs, watching videos, browsing the net, preparing a word document to something as simple as a mouse click.
So the processor is responsible for interpreting every code it receives from the other computer components, and making it usable to your operating system

3. Major Parts of a Processor
The Arithmetic Logic Unit (ALU)
It performs math and logical operations
The Control Unit,
It decodes instructions.
Over the years, processors have become extremely fast in terms of how long it takes to execute an instruction.
AMD and Intel are the two primary manufacturers

4. CPU Package and Socket
When looking at a CPU, you don't really see the processor itself. What you actually see is the package that contain the processor.
Packages are usually square with pins underneath that fit into holes on the CPU's socket (Pin Grid) or the pins may be located on the sockets themselves (Land Grid) and the package is slotted into the pins.
The socket refers to a physical connector on a computer motherboard that accepts a single physical chip. Many motherboards can have multiple sockets that can in turn accept multi-core chips. 

5. Land Grid Array
Intel uses Land Grid Array technology where the pins that connect the processor and the motherboard are on the socket, not on the processor.
The socket provides input/output power and ground contacts. An LGA socket's number tells you how many pins it has. For example, an LGA 775 has 775 pins and an LGA 1155 contains 1,155 socket pins, each of which is individually soldered to the motherboard.

6. Land Grid Array

7. Pin Grid Array
AMD uses the Pin Grid Array a technology that places the pins that connect the motherboard and the processor on the processor, instead of on the socket. 
 AMD doesn't use the PGA term to label the sockets. The type of socket determines the number of pins e.g. AM2 contains 940 pins. Other packages have 754, 939 pins

8. Pin Grid Array

9. Pin Grid Array
AM2+ and AM3 mainly differ in terms of the memory each supports. AM2+ supports DDR2 while AM3 supports DDR2 and DDR3, making it backward-compatible with the AM2+ motherboard

10. Processor Sockets
 CPU socket is the spot on the motherboard, generally a square shape, where you install or "plug in" a computer processor.
The socket provides power and connects the CPU to the rest of the computer. This means it provides mechanical and electrical connections between the CPU and motherboard. This allows the CPU to be replaced without soldering.

11. Processor Sockets
Processors are designed to fit into a certain type of socket on the motherboard and every socket has a name, indicating whether it's for an AMD or Intel CPU.
AMD and Intel have different socket designs, so their processors are not interchangeable. But regardless of manufacturer, CPUs usually differ in the number of pins used.

12. Types of Processors Socket Type Manufacturer LGA 771 (Socket J) Intel
LGA 775 (Socket T)
LGA 1156 (Socket H)
LGA 1166 (Socket B)
AM2
AMD
AM2+
AM3

13. Processor Speed (Clock Speed)
Every computer contains an internal clock that regulates the speed at which instructions are executed.
The CPU requires a fixed number of clock ticks (or clock cycles) to execute each instruction. The faster the clock, the more instructions the CPU can execute per second
So while an older CPU might need 20 cycles to multiply two numbers, a newer version processor can perform the same calculation in a single clock tick. Other can perform more than one instruction per clock cycle.

14. Processor Speed (Clock Speed)
So what characterizes a computer processor is its speed i.e. how fast it can execute instructions.
Currently the speed is measured in Gigahertz (GHz), or billions of cycles a second. Some CPU rates are 2.0 GHz, 2.40 GHz, and 3.20 GHz. These rates and others are obtained by using the motherboard's bus speed. 
CPUs contain a multiplier that when multiplied by the bus speed, yields the appropriate CPU speed for a given motherboard. For example, if the speed of a motherboard is 800 MHz, and the CPU multiplier is 4, then the processor's speed is 800 x 4 = 3200 MHz or 3.2 GHz. 

15. Processor Speed
Due to the fact that the CPU speed greatly determines the overall performance of a PC, the type of processor and its speed are two of the main factors to look for when deciding to buy a computer.
Howevre there are other important things, such as the amount of memory. 

16. CPU Cache
In addition to CPU speed, another important processor feature that influences performance is the amount of cache it has. CPU cache is memory set aside for the most frequently used data. There 3 levels of CPU cache.
Level 1
Level 2
Level 3
They are commonly just called L1, L2, and L3 and they mainly reduce the average time to access data from the main memory.

17. CPU Cache
L1 also known as primary cache uses extremely fast and expensive SRAM (Static RAM) and is the smallest in size.
L2 is slightly larger in size. Both L1 and L2 are located on the processor.
L3 is the largest and is usually located outside the CPU and shared by all the cores.
When data is requested, the CPU first checks the L1 to see if it's there. If not it checks L2 and then the L3. Accessing data in the cache is far faster and efficient than fetching it from RAM. 

18. CPU Core, and Hyper-threading
A core is simply one CPU on a motherboard. It can run a single program or multiple programs if it supports hyper-threading technology. A CPU may have one or more cores to perform tasks at a given time. These tasks are usually software processes and threads that the OS schedules.
Hyper-Threading is an Intel technology that improved parallel computation i.e. doing multiple tasks at the same time. So a single physical CPU core with hyper-threading appears as two logical CPUs to an operating system.

19. Multi-Core Processors
Originally, CPUs had a single core and this meant the physical CPU had a single central processing unit on it. To increase performance, manufacturers added additional “cores,” or central processing units.
So a dual-core CPU has two central processing units, so it appears to the operating system as two CPUs. A different process can be using each core at the same time. This speeds up your system, because your computer can do multiple things at once.

20. Multi-core Processors
Computer processors today are either dual core or quad-core. Both terms are generic for any processor that literally contains two or more CPUs in one package.
Multi-core examples are the AMD Phenom x3 and x4 and Intel's Core 2 Quad and the Core i7. These powerful CPUs allow users to run several applications simultaneously as well as play the latest games. 
Intel Itanium processors has 2,4, or 8 cores

21. HyperTransport:
AMD's HyperTransport Technology has been around since All of its processors based on AMD64 architecture use HyperTransport. It eliminated the front side bus (FSB) and took the memory controller, which was previously on the chipset, and placed it on the processor.
The old front side bus used one data path from the CPU for memory input and output. HTT implements two separate data paths for memory and I/O. Also, unlike the FSB, data flow between the CPU and the memory can be sent and received at the same time.

22. QuickPath Interconnect
In late 2008, Intel released the quad-core Core i7 CPU with its own version of HyperTransport called QuickPath Interconnect (QPI). It basically does the same thing as HTT but only uses DDR3 memory, and depending on which model some support three memory channels.  

23. END OF LECTURE