CPU Facts

• Intel and AMD are the two producers of processors      used in modern PCs.      
• Both Intel and AMD processors work in PC  systems and support Windows software.        
• Intel has a larger market share, while AMD  processors generally cost less.
• Processor performance and special features   vary between models and manufacturers.

• A 32-bit processor can process 32-bits of      information at a time
• 32-bit processors        have        a limit of 4GB
• The processor instruction set identifies        all instructions (operations) that a processor can perform.         
•         32-bit processors use the IA-32 instruction set (also referred to as x86).           
•          Itanium processors from Intel use the IA-64 instruction set.          
•          AMD64 and Intel 64 processors use the x86-64 instruction set (also referred to as x64). 
• 32-bit applications can run on 64-bit processors  using the following methods:        
•           Itanium processors use a software layer to translate between IA-32 and IA-64.          
•          x64 processors execute both 32-bit and 64-bit  instructions in the hardware.

a 64-bit processor can process 64-bits of information. Over the last several years, processors have been moving from 32-bit processors to 64-bit processors.

• The biggest advantage of 64-bit processors over 32-bit processors is in the amount of memory they can use. 32-bit processors have a limit of 4GB. 64-bit processors have a  theoretical limit of 16.8 TB, although operating system and current hardware limitations impose a much lower practical limit. The operating system and applications must be written for 64-bits to take full advantage of 64-bit processing.        The processor instruction set identifies        all instructions (operations) that  a processor can perform.         32-bit processors use the IA-32 instruction          set (also referred to as x86).           
• Itanium processors from Intel use the IA-64 instruction set.          
• AMD64 and Intel 64 processors use the x86-64 instruction set (also referred to as x64).        
• 32-bit applications can run on 64-bit processors using the following methods:         Itanium processors use a software layer to translate between IA-32 and IA-64.           x64 processors execute both 32-bit and 64-bit instructions in the hardware.          Applications typically perform better on        64-bit systems.         64-bit applications typically perform better          than 32-bit applications.           In some cases, 32-bit applications might          perform better on 64-bit systems.

Processors operate using an internal clock      that is the same as, or is a multiple of, the      motherboard bus speed. The speed is represented      in MHz and is also referred to as the frequency.       You can purchase processors of the same type        but with different speed ratings.          When selecting a processor, make sure the        motherboard supports the processor speed by reading the motherboard documentation first.         Most motherboards automatically detect the        processor speed. If not, you might need to        use jumpers or edit the CMOS to configure        the processor speed.

A multiple core processor has multiple processors      within a single processor package.       Dual-core, triple-core, and quad-core processors are typical in desktop systems. Multi-core systems enable the operating system        to run multiple applications simultaneously.        Without multiple processors, applications        appear to run at the same time, but must        wait their turn for processing time from        the single processor.         Some applications can be written to execute        on multiple processors at the same        time.                 Older motherboards had two (or more) processor        sockets to provide a multiple processor solution.        Newer multi-core processors use a single        motherboard socket to support multiple processors.

• Cache is memory that the processor can access      directly without using the system RAM. There      are three types of processor cache:      
• Level 1 (L1) cache is integrated on the processor die itself and stores instructions for the processor. On multi-core systems, each processor typically has its own L1 cache. Some processors might have two L1 caches, one for instructions and one for data.  
• Level 2 (L2) cache is additional cache used for both instructions and data. Depending on the processor, L2 cache might be shared        between two or more cores, or exclusive to a single core.         
• Level 3 (L3) cache is additional cache beyond the level 2 cache.
• For multi-core systems,  L3 cache is shared between all cores.            

• Be aware of the following regarding      processor cache:      
• The size of the cache increases as you move from L1 to L3, with L1 cache being        the smallest. As a general rule, a processor with more cache performs better than a processor with less cache (all other things being equal).  
• Originally, only L1 cache was on the processor  die, with L2 cache being on the motherboard between the CPU and the RAM. As processor technology has advanced, L2 cache moved to the processor die, with L3 cache being on  the motherboard.
• Today, all three cache levels are located on the processor.

The process size refers to the manufacturing process used to etch transistors onto the silicon wafer that will become the CPU. A smaller process size means smaller transistors, which translates into a smaller CPU die with more transistors and less power consumption. Process size is expressed in microns (such as .25 microns)      or nanometers (90 nm which equals .09      microns).

Hyper-threading is a feature of some Intel processors that      allows a single processor to run threads      (instructions) in parallel, as opposed to      processing threads linearly. Hyper-threading      enables a processor to execute two threads      at the same time. For example, on a quad-core      Intel system that supports hyper-threading,      the processor can execute 8 threads at a      time (2 on each core).       Hyper-threading is not the same as multithreading.       Multithreading is a feature of an application that allows      it to send multiple threads at the same time.      Applications are typically written to support      multithreading to take advantage of multiple      cores (executing threads on two or more processors      at the same time) or hyper-threading features.

Throttling is the process of modifying the operating      characteristics of a processor based      on current      conditions.       Throttling is often used in mobile processors        to change the operating frequency to minimize        power consumption and heat output.         Throttling can also be used in low memory        conditions to slow down the processing of        I/O memory requests, processing one sequence        at a time in the order the request was received.         Related to throttling, processors or the        operating system can shut down unused cores        in multi-core systems to conserve energy.             Some Intel processors include a Turbo Boost      feature. Turbo Boost, the opposite of throttling,      allows the processor to dynamically run above      its rated speed to improve performance.

Mobile CPUs are used in notebook computers      where portability and mobility are a concern.      Special versions of processors are built      to minimize power consumption and the amount      of heat generated.

Virtualization allows a single physical machine (known      as the host operating system) to run multiple virtual      machines (known as the guest operating systems). The virtual machines      appear to be self-contained and separate      physical systems.       Virtualization is performed by adding a layer        between the physical system and the operating        system. This layer acts as the hardware to        the guest system.          Early virtualization was performed using        software only. Newer virtualization        uses        special instructions supported by        the processor        to improve performance.          VMware is the most popular virtualization        solution. Microsoft has several virtualization        products including Virtual PC, Virtual        Server,        and Hyper-V.         If you are planning on implementing a virtual        solution, check to see whether hardware        support        in the CPU is required. Hardware        support        is provided by processors with the        following        features:         Intel's Virtualization Technology (VT)           AMD's AMD Virtualization (AMD-V)

In a traditional processor design, the processor      is connected to the front side bus and the      Northbridge chip. The processor communicates      with other system components through the      front side bus. Smaller manufacturing size      has reduced the overall size of a processor,      leaving more room on the processor die for      additional cores or cache. To improve performance,      some processors include the memory controller      on the processor die rather than in the Northbridge      chip, resulting in faster memory access by      the processor.

Processors require some form of heat dissipation      system to function properly. Without a heat      dissipation system, a processor will overheat      and burn out in less than a minute. Most      modern CPUs require a heat sink and a fan.      Between the CPU and the heat sink, thermal      paste or a thermal pad helps in the transfer      of heat from the CPU to the cooling unit.

• If two processors are of the same type, higher speed  typically means higher performance. With  processors of different types, speeds might  not be comparable.   It is important to make sure your mother board can support the speed of your processor.
• Many processors use a performance rating  instead of speed with a higher number indicating  a better-performing processor. However, performance  ratings are typically only applicable between  models of the same manufacturer.   In some cases, buying a processor with double  the cache can nearly double the performance.   Dual core processors offer better performance,  but typically not double. Software must be  specially written to take best advantage  of the dual core processors.   Special instruction sets supported by a processor  can increase performance. For example, hyperthreading  support on Intel processors can boost performance  for specific types of operations.   Performance can also be increased by modifying other  system components such as adding more  RAM, using a faster disk, or improving cooling and ventilation.   Overclocking is a feature that causes the processor to  operate at a higher speed. Overclocking is  typically performed by those who want to  get the maximum performance from their systems.  Some important things to know about overclocking  are:   Overclocking can cause system instability,    component damage, and can void your warranty.
• Motherboard bus, processor, and memory settings    should be adjusted to match. Overclocking may require more voltage.
• Overclocking often increases heat output.    For this reason, it may be necessary to upgrade your cooling devices.

32 nm

The ability to use over 4 GB of memory

Throttling

• 64 bit processor use th x86-64 instructions set also referred to as x64
• 32 bit processors use only the IA-32 instructions set also referred to as x86

Allows a processor to access data more quickly

• Voided warranty
• increase heat output

Performance will depend on other factors such as cache and other features.

• l1 is typically unique to a processor core
• L3 is shared between all cores

Multi-core

A special socket for inserting and securing a processor

Hyper-threading

Overclocking

multiply processor sockets on the motherboard