What is a Dual Core Processor?

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A dual core processor for a computer is a central processing unit (CPU) that has two separate cores on the same die, each with its own cache. It essentially is two microprocessors in one. This type of CPU is widely available from many manufacturers. Other types of multi-core processors also have been developed, including quad-core processors with four cores each, hexa-core processors with six, octa-core processors with eight and many-core processors with an even larger number of cores.

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What is a Dual Core Processor?

  1. 1. CONTENT WHAT IS DUAL CORE PROCESSORWHAT IS DUAL CORE PROCESSOR? SOME DETAILS ABOUT DUAL CORESOME DETAILS ABOUT DUAL CORE?? HOW IT IS DIFFERENT FROM SINGLECORE PROCESSORHOW IT IS DIFFERENT FROM SINGLECORE PROCESSOR?? WHAT IS ITS UTILITIESWHAT IS ITS UTILITIES?? HOW IT IS DIFFERENT FROM MULTIPROCESSOR SYSTEMHOW IT IS DIFFERENT FROM MULTIPROCESSOR SYSTEM?? PARALLEL PROCESSING OF CPUPARALLEL PROCESSING OF CPU?? CACHE OF DUAL CORECACHE OF DUAL CORE?? DISK CACHINGDISK CACHING?? ABOUT TFLOPABOUT TFLOP?? CLOCK SPEEDCLOCK SPEED?? ADVANTAGEADVANTAGE?? CONCLUSIONCONCLUSION??
  2. 2. DUAL CORE PROCESSOR A dual core processor is a CPU with two separate cores on the same die, each with its own cache. It's the equivalent of getting two microprocessors in one. BACK
  3. 3. SOME DETAILS ABOUT DUAL CORE BACK dual core chip is that tasks can be carried out in parallel streams, decreasing processing time. This is referred to as thread-level parallelism (TLP). TLP is also possible on motherboards that can accommodate two separate CPU dies. When TLP is accomplished in a single CPU through dual core technology, it is called chip-level multiprocessing (CLM). In dual core CPUs, each microprocessor generally has its own on- board cache, known as Level 1 (L1) cache. L1 cache significantly improves system performance, because it is much faster to access on- chip cache than to use random access memory (RAM). L1 cache is accessed at microprocessor speeds. Dual core chips also commonly feature secondary shared cache on the CPU, known as Level 2 (L2) cache. Motherboards may also have a cache chip designated as Level 3 (L3) cache. While faster than RAM, L3 cache is slower than cache built into the dual core chip.
  4. 4. DIFFERENT FROM SINGLECOREDIFFERENT FROM SINGLECORE PROCESSORPROCESSOR In a single-core or traditional processor the CPU is fed strings of instructions it must order, execute, then selectively store in its cache for quick retrieval. When data outside the cache is required, it is retrieved through the system bus from random access memory (RAM) or from storage devices. Accessing these slows down performance to the maximum speed the bus, RAM or storage device will allow, which is far slower than the speed of the CPU. The situation is compounded when multi- tasking. In this case the processor must switch back and forth between two or more sets of data streams and programs. CPU resources are depleted and performance suffers. In a dual core processor each core handles incoming data strings simultaneously to improve efficiency. Just as two heads are better than one, so are two hands. Now when one is executing the other can be accessing the system bus or executing its own code. Adding to this favorable scenario, both AMD and Intel's dual-core flagships are 64-bit. BACK
  5. 5. ITS UTILITIESITS UTILITIES To utilize a dual core processor, the operating system must be able to recognize multi-threading and the software must have simultaneous multi- threading technology (SMT) written into its code. SMT enables parallel multi-threading wherein the cores are served multi-threaded instructions in parallel. Without SMT the software will only recognize one core. Adobe Photoshop is an example of SMT-aware software. SMT is also used with multi-processor systems common to servers. BACK
  6. 6. DIFFERENT FROM MULTI PROCESSORDIFFERENT FROM MULTI PROCESSOR SYSTEMSYSTEM A dual core processor is different from a multi-processor system. In the latter there are two separate CPUs with their own resources. In the former, resources are shared and the cores reside on the same chip. A multi- processor system is faster than a system with a dual core processor, while a dual core system is faster than a single-core system, all else being equal. An attractive value of dual core processors is that they do not require a new motherboard, but can be used in existing boards that feature the correct socket. For the average user the difference in performance will be most noticeable in multi-tasking until more software is SMT aware. Servers running multiple dual core processors will see an appreciable increase in performance. BACK
  7. 7. PARALLEL PROCESSING OF CPUPARALLEL PROCESSING OF CPU Parallel processing is the simultaneous processing of the same task on two or more microprocessors in order to obtain faster results. The computer resources can include a single computer with multiple processors, or a number of computers connected by a network, or a combination of both. The processors access data through shared memory. Some supercomputer parallel processing systems have hundreds of thousands of microprocessors. With the help of parallel processing, a number of computations can be performed at once, bringing down the time required to complete a project. Parallel processing is particularly useful in projects that require complex computations, such as weather modeling and digital special effects. Let's take a real-life example to understand the efficacy of parallel processing. BACK
  8. 8. CACHE OF DUAL CORECACHE OF DUAL CORE Cache (pronounced cash) memory is extremely fast memory that is built into a computer’s central processing unit (CPU), or located next to it on a separate chip. The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cache memory is that the CPU does not have to use the motherboard’s system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard’s capability. The CPU can process data much faster by avoiding the bottleneck created by the system bus. As it happens, once most programs are open and running, they use very few resources. When these resources are kept in cache, programs can operate more quickly and efficiently. All else being equal, cache is so effective in system performance that a computer running a fast CPU with little cache can have lower benchmarks than a system running a somewhat slower CPU with more cache. Cache built into the CPU itself is referred to as Level 1 (L1) cache. Cache that resides on a separate chip next to the CPU is called Level 2 (L2) cache. Some CPUs have both L1 and L2 cache built-in and designate the separate cache chip as Level 3 (L3) cache. Cache that is built into the CPU is faster than separate cache, running at the speed of the microprocessor itself. However, separate cache is still roughly twice as fast as Random Access Memory (RAM). Cache is more expensive than RAM, but it is well worth getting a CPU and motherboard with built-in cache in order to maximize system performance. BACK
  9. 9. DISK CACHINGDISK CACHING Disk caching applies the same principle to the hard disk that memory caching applies to the CPU. Frequently accessed hard disk data is stored in a separate segment of RAM in order to avoid having to retrieve it from the hard disk over and over. In this case, RAM is faster than the platter technology used in conventional hard disks. This situation will change, however, as hybrid hard disks become ubiquitous. These disks have built-in flash memory caches. Eventually, hard drives will be 100% flash drives, eliminating the need for RAM disk caching, as flash memory is faster than RAM. BACK
  10. 10. ABOUT TFLOPABOUT TFLOP A tflop, or teraflop, system is a parallel supercomputing system that has the ability to compute one trillion floating point operations in a single second. This term applies in many ways to the basic systems that run database systems. The tflop system is not the first parallel supercomputing system to be created, although it has become the most used. The Intel Paragon was in existence before the tflop and is also a parallel processing system. Each of these systems is a reliable option. The tflop system, however, is not as difficult to program as the Intel Paragon system. The N-cube system preceded the Intel Paragon, but this is an outdated system and very rarely used. BACK
  11. 11. CLOCK SPEEDCLOCK SPEED Clock speed is a measure of how quickly a computer completes basic computations and operations. It is measured as a frequency in hertz, and most commonly refers to the speed of the computer's CPU, or Central Processing Unit. Since the frequency most clock speed measures is very high, the terms megahertz and gigahertz are used. A megahertz is one-million cycles per second, while a gigahertz is one-billion cycles per second. So a computer with a clock speed of 800MHz is running 800,000,000 cycles per second, while a 2.4GHz computer is running 2,400,000,000 cycles per second. BACK
  12. 12. ADVANTAGEADVANTAGE Dual core technology has advantages over double-core or twin-core technology. These latter terms refer to two independent CPUs installed on the same motherboard. Dual core chips take up less real estate on the motherboard, have greater cache coherency, and consume less power than two independent CPUs. However, dual core technology also has its drawbacks. For software to take advantage of dual core architecture, it must be written to utilize parallel threading. Otherwise, the program functions in single-core mode, using just one data stream or one of the built-in microprocessors. Unfortunately, coding for TLP is quite intensive, as interleaving shared data can create errors and slow performance. Because of these and other issues, a Dual Core Processor does not deliver twice the speed of a single-core processor, though there is a significant increase in performance under optimal conditions. Finally, dual core chips run hotter than their single-core cousins. Whether a dual core processor is right for you will depend on what you plan to use your computer for. If the programs you regularly require are designed for TLP, then you may benefit greatly from a dual core chip. If not, you may be better served by a high-end single-core CPU. BACK
  13. 13. CONCLUSIONCONCLUSION If you haven’t done so already, now is the time to take a hard look at the design of your application, determine what operations are CPU-sensitive now or are likely to become so soon, and identify how those places could benefit from concurrency. A few rare classes of applications are naturally parallelizable, but most aren’t. Even when you know exactly where you’re CPU-bound, you may well find it difficult to figure out how to parallelize those operations; all the most reason to start thinking about it now. Implicitly parallelizing compilers can help a little, but don’t expect much; they can’t do nearly as good a job of parallelizing your sequential program as you could do by turning it into an explicitly parallel and threaded version. Thanks to continued cache growth and probably a few more incremental straight- line control flow optimizations, the free lunch will continue a little while longer; but starting today the buffet will only be serving that one entrée and that one dessert. The filet mignon of throughput gains is still on the menu, but now it costs extra— extra development effort, extra code complexity, and extra testing effort. The good news is that for many classes of applications the extra effort will be worthwhile, because concurrency will let them fully exploit the continuing exponential gains in processor throughput. BACK

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