What is a Computer Processor or Central Processing Unit (CPU)??
The processor or the central processing unit (CPU) is the portion of a computer system that carries out the instructions of a computer.The CPU (Central Processing Unit) is essentially the brain of the computer. It interprets and executes instructions and data contained in software programs. The more generic term "processor" is often used to refer to a CPU as well, and the more specific term "microprocessor", meaning CPUs that are manufactured on integrated circuits, is also widely used nowadays. These three words mean exactly the same thing in this article, and elsewhere in most cases. As the brain of a computer, the processor (or CPU) plays a defining role in the total PC system. The performance of a PC system is roughly determined by the processor, so choosing the right processor is key when building your own computer. The other components, such as RAM and hard disk drive, also play important roles, while the video card is crucial when it comes to 3D graphics performance.
The CPU speed, or processor speed, is the amount of cycles that a CPU can perform per second. This is otherwise known as a Hertz. For example, one Hertz means that one cycle can be completed in one second. A megahertz means that one million cycles can be completed in a second. A gigahertz, the most common form of processor speed, means that one billion cycles can be completed per second.
Does this mean that a 2GHz CPU is twice as fast as a 1Ghz CPU?
Not necessarily. This depends on how much work each CPU accomplishes in each clock cycle.
The 1GHz CPU might very well be faster, in practice, than the 2Ghz CPU if it is more efficient or can process more tasks in each CPU cycle, which depends on its architecture.Modern CPUs typically have multiple cores, such as dual-core, quad-core, and even 6-core CPUs. This multiplies the amount of cycles a CPU can make per second, as each core can perform its cycles in parallel to the other cores. That’s just one way two CPUs both rated at 2Ghz, for example, can still have different real speeds. If one has more core than the other it can do more in less time. There are other elements of CPU architecture that factor in its real world speed, however.
The Cache
A cache enables the CPU to access recently used information very quickly.A cache significantly affects CPU performance.However, caches also represent some difficulties in simple comparison.Some caches are bigger than others. A typical L1 cache is 256Kb and a typical L2 cache is 1MB.Generally speaking, the larger the cache, the better the system performance boost. However, this is not always the case.A cache operates at a certain speed, just like the CPU’s core. Some caches operate at the full speed of the CPU, while others
operate at half that speed or less.
A small cache that operates at full speed may be much more useful than a cache that is twice as large but operates at only half the speed of the CPU.Even comparing cache sizes can be difficult. Some CPUs utilize inclusive caches. In a CPU with an exclusive cache, the data stored in the L1 cache is often duplicated in the L2 cache. Only CPUs that employ exclusive caches will have the full capacity of their L2 caches available.
The Front Side Bus
The Front Side Bus (FSB) is the connection between the CPU and system memory.The Front Side Bus operates at a speed that is a percentage of the CPU clock speed.The faster the speed at which the Front Side Bus allows data transfer, the better the CPU performance.
System Memory
RAM has an access speed. Faster RAM means that the CPU has to wait less often for data. This effectively makes the CPU faster. The amount of system memory matters as well. The more system memory is available more applications can run at the same time, requiring less reliance on “swapping”, or the use of hard drive space for virtual memory. Swapping can seriously affect the performance of the system because hard drives have far lower access speeds than RAM.
The Rest of the System
Everything in the system affects total system performance, from the rotational speed and access time of the hard disk drive to the speed of video RAM and the GPU (Graphical Processing Unit) in the graphics card.
Benchmarking
The next possible answer for measuring CPU speed and overall system performance is benchmarking.
Unfortunately, benchmarks are necessarily flawed. A benchmark can only prove how quickly a system runs the benchmark. A benchmark cannot show how quickly a system will run a user’s mix of applications in the real world.
Overclocking
While a CPU is intended to run safely at a certain clock rate set by the manufacturer, it can often support
even greater rates, and these maximum values are typically published by manufacturers for those who would wish to force the CPU to run faster.This practice is known as “overclocking”, and results in the CPU running even more cycles per second than it is rated for, doing more work in less time. This could mean making the CPU rated at 2Ghz run at 2.4Ghz instead, for example. If one processor has a better and more efficient architecture than the other, but both run at 2 Ghz, the one with the better architecture will be faster in
practice. However, if the processor with the worse architecture is overclocked to run on 2.4Ghz, it could possibly make up for or exceed the performance gap.
Overclocking, however, carries some risks. Since it typically involves pushing the CPU to operate beyond the rates deemed safe by the manufacturer, even if the CPU can theoretically handle them, it can cause the CPU to give off more heat, and in the process possibly lower its life span. More heat can also lead to some instability in its operation. This is why overclockers typically fit better cooling mechanisms on their CPUs to further help cool the CPU.
The Good News
The good news is that almost any new PC will be fast enough to run most applications reasonably well.If the user believes that his/her application has special requirements, he/she should read the application documentation or contact the application vendor.The most popular processors are manufactured by Intel.
What is a Core in A Processor?
The "core" in a processor is the microprocessor inside of the CPU(Central Processing Unit).
For example, if you have a Dual Core CPU then you have 2 microprocessors inside of the CPU, this allows you to do two things at once or if you have a core i7 CPU then you have 7 microprocessors inside of the CPU which allows you to do seven things at once, as a microprocessor can only do one thing at a time the only exception to this is Multi-Threading which allows one core to do the work of multiple cores, but its not as fast as having multiple cores.
Intel Core
Intel Core (stylized and marketed as intel CORE as of 2009) is a brand name that Intel uses for various mid-range to high-end consumer and business microprocessors. In general, processors sold as Core are more powerful variants of the same processors marketed as entry-level Celeron and Pentium. Similarly, identical or more capable versions of Core processors are also sold as Xeon processors for the server and workstation market.As of 2013 the current lineup of Core processors includes the latest Intel Core i7, Intel Core i5, and Intel Core i3, and the older Intel Core 2 Solo, Intel Core 2 Duo, Intel Core 2 Quad, and Intel Core 2 Extreme lines.Intel processors have been manufactured under the following architectures Enhanced Pentium M based, 64-bit Core Micro-architecture based,Nehalem Microarchitecture based , Sandy Bridge Microarchitecture based
A quick look at the various Intel processors on the market for desktops and laptops.
The original Core brand refers to Intel's 32-bit mobile dual-core x86 CPUs, which derived from the Pentium M branded processors. The processor family used a more enhanced version of the Intel P6 microarchitecture. It emerged in parallel with the NetBurst microarchitecture (Intel P68) of the Pentium 4 brand, and was a precursor of the 64-bit Core microarchitecture of Core 2 branded CPUs. The Core brand comprised two branches: the Duo (dual-core) and Solo (Duo with one disabled core, which replaced the Pentium M brand of single-core mobile processor).
Intel launched the Core brand on January 6, 2006 with the release of the 32-bit Yonah CPU – Intel's first dual-core mobile (low-power) processor. Its dual-core layout closely resembled two interconnected Pentium M branded CPUs packaged as a single die (piece) silicon chip (IC). Hence, the 32-bit microarchitecture of Core branded CPUs – contrary to its name – had more in common with Pentium M branded CPUs than with the subsequent 64-bit Core microarchitecture of Core 2 branded CPUs. Despite a major rebranding effort by Intel starting January 2006, some companies continued to market computers with the Yonah core marked as Pentium M.
The Core series is also the first Intel processor used as the main CPU in an Apple Macintosh computer. The Core Duo was the CPU for the first generation MacBook Pro, while the Core Solo appeared in Apple's Mac mini line. Core Duo signified the beginning of Apple's shift to Intel processors across their entire line.
In 2007, Intel began branding the Yonah core CPUs intended for mainstream mobile computers as Pentium Dual-Core, not to be confused with the desktop 64-bit Core microarchitecture CPUs also branded as Pentium Dual-Core.September 2007 and January 4, 2008 marked the discontinuation of a number of Core branded CPUs including several Core Solo, Core Duo, Celeron and one Core 2 Quad chip.
Core Duo
Intel Core Duo[4] (product code 80539) consists of two cores on one die, a 2 MB L2 cache shared by both cores, and an arbiter bus that controls both L2 cache and FSB (front-side bus) access.
Intel Core Solo (product code 80538) uses the same two-core die as the Core Duo, but features only one active core.Depending on demand, Intel may also simply disable one of the cores to sell the chip at the Core Solo price—this requires less effort than launching and maintaining a separate line of CPUs that physically only have one core. Intel used the same strategy previously with the 486 CPU in which early 486SX CPUs were in fact manufactured as 486DX CPUs but with the FPU disabled.
64-bit Core micro-architecture based
Core (Microarchitecture)
The successor to Core is the mobile version of the Intel Core 2 line of processors using cores based upon the Intel Core microarchitecture,[6] released on July 27, 2006. The release of the mobile version of Intel Core 2 marks the reunification of Intel's desktop and mobile product lines as Core 2 processors were released for desktops and notebooks, unlike the first Intel Core CPUs that were targeted only for notebooks (although some small form factor and all-in-one desktops, like the iMac and the Mac Mini, also used Core processors).
Unlike the Intel Core, Intel Core 2 is a 64-bit processor, supporting Intel 64. Another difference between the original Core Duo and the new Core 2 Duo is an increase in the amount of Level 2 cache. The new Core 2 Duo has tripled the amount of on-board cache to 6 MB. Core 2 also introduced a quad-core performance variant to the single- and dual-core chips, branded Core 2 Quad, as well as an enthusiast variant, Core 2 Extreme. All three chips are manufactured at a 65 nm lithography, and in 2008, a 45 nm lithography and support Front Side Bus speeds ranging from 533 MHz to 1600 MHz. In addition, the 45 nm die shrink of the Core microarchitecture adds SSE4.1 support to all Core 2 microprocessors manufactured at a 45 nm lithography, therefore increasing the calculation rate of the processors.
Core 2 Solo
The Core 2 Solo,introduced in September 2007, is the successor to the Core Solo and is available only as an ultra-low-power mobile processor with 5.5 Watt thermal design power. The original U2xxx series "Merom-L" used a special version of the Merom chip with CPUID number 10661 (model 22, stepping A1) that only had a single core and was also used in some Celeron processors. The later SU3xxx are part of Intel's CULV range of processors in a smaller µFC-BGA 956 package but contain the same Penryn chip as the dual-core variants, with one of the cores disabled during manufacturing.
Core 2 Duo
The majority of the desktop and mobile Core 2 processor variants are Core 2 Duo[8][9] with two processor cores on a single Merom, Conroe, Allendale, Penryn, or Wolfdale chip. These come in a wide range of performance and power consumption, starting with the relatively slow ultra-low-power Uxxxx (10 W) and low-power Lxxxx (17 W) versions, to the more performance oriented Pxxxx (25 W) and Txxxx (35 W) mobile versions and the Exxxx (65 W) desktop models. The mobile Core 2 Duo processors with an 'S' prefix in the name are produced in a smaller µFC-BGA 956 package, which allows building more compact laptops.Within each line, a higher number usually refers to a better performance, which depends largely on core and front-side bus clock frequency and amount of second level cache, which are model-specific. Core 2 Duo processors typically use the full L2 cache of 2, 3, 4, or 6 MB available in the specific stepping of the chip, while versions with the amount of cache reduced during manufacturing are sold for the low-end consumer market as Celeron or Pentium Dual-Core processors. Like those processors, some low-end Core 2 Duo models disable features such as Intel Virtualization Technology.
Core 2 Quad
Core 2 Quad processors are multi-chip modules consisting of two dies similar to those used in Core 2 Duo, forming a quad-core processor. This allows twice the performance of a dual-core processors at the same clock frequency in ideal conditions.
Initially, all Core 2 Quad models were versions of Core 2 Duo desktop processors, Kentsfield derived from Conroe and Yorkfield from Wolfdale, but later Penryn-QC was added as a high-end version of the mobile dual-core Penryn.The Xeon 32xx and 33xx processors are mostly identical versions of the desktop Core 2 Quad processors and can be used interchangeably.
Core 2 Extreme
Core 2 Extreme processors are enthusiast versions of Core 2 Duo and Core 2 Quad processors, usually with a higher clock frequency and an unlocked clock multiplier, which makes them especially attractive for overclocking. This is similar to earlier Pentium processors labeled as Extreme Edition. Core 2 Extreme processors were released at a much higher price than their regular version, often $999 or more.
Nehalem microarchitecture based
With the release of the Nehalem microarchitecture in November 2008,Intel introduced a new naming scheme for its Core processors. There are three variants, Core i3, Core i5 and Core i7, but the names no longer correspond to specific technical features like the number of cores. Instead, the brand is now divided from low-level (i3), through mid-range (i5) to high-end performance (i7),[15] which correspond to three, four and five stars in Intel's Intel Processor Rating[16] following on from the entry-level Celeron (one star) and Pentium (two stars) processors.Common features of all Nehalem based processors include an integrated DDR3 memory controller as well as QuickPath Interconnect or PCI Express and Direct Media Interface on the processor replacing the aging quad-pumped Front Side Bus used in all earlier Core processors. All these processors have 256 KB L2 cache per core, plus up to 12 MB shared level 3 cache. Because of the new I/O interconnect, chipsets and mainboards from previous generations can no longer be used with Nehalem based processors.
Core i3
Intel intended the Core i3 as the new low end of the performance processor line from Intel, following the retirement of the Core 2 brand.The first Core i3 processors were launched on January 7, 2010.
The first Nehalem based Core i3 was Clarkdale-based, with an integrated GPU and two cores.The same processor is also available as Core i5 and Pentium, with slightly different configurations.The Core i3-3xxM processors are based on Arrandale, the mobile version of the Clarkdale desktop processor. They are similar to the Core i5-4xx series but running at lower clock speeds and without Turbo Boost.According to an Intel FAQ they do not support Error Correction Code (ECC) memory.According to motherboard manufacturer Supermicro, if a Core i3 processor is used with a server chipset platform such as Intel 3400/3420/3450, the CPU will support ECC with UDIMM.[When asked, Intel confirmed that, although the Intel 5 series chipset supports non-ECC memory only with the Core i5 or i3 processors, using those processors on a motherboard with 3400 series chipsets it will support the ECC function of ECC memory.A limited number of motherboards by other companies also support ECC with Intel Core ix processors; the Asus P8B WS is an example, but it does not support ECC memory under Windows non-server operating systems.
Core i5
The first Core i5 using the Nehalem microarchitecture was introduced on September 8, 2009, as a mainstream variant of the earlier Core i7, the Lynnfield core.Lynnfield Core i5 processors have an 8 MB L3 cache, a DMI bus running at 2.5 GT/s and support for dual-channel DDR3-800/1066/1333 memory and have Hyper-threading disabled. The same processors with different sets of features (Hyper-Threading and other clock frequencies) enabled are sold as Core i7-8xx and Xeon 3400-series processors, which should not be confused with high-end Core i7-9xx and Xeon 3500-series processors based on Bloomfield.
The Core i5-5xx mobile processors are named Arrandale and based on the 32 nm Westmere shrink of the Nehalem microarchitecture. Arrandale processors have integrated graphics capability but only two processor cores. They were released in January 2010, together with Core i7-6xx and Core i3-3xx processors based on the same chip. The L3 cache in Core i5-5xx processors is reduced to 3 MB, while the Core i5-6xx will use the full cache and the Core i3-3xx will have no support for Turbo Boost.[29] Clarkdale, the desktop version of Arrandale, is sold as Core i5-6xx, along with related Core i3 and Pentium brands. It has Hyper-Threading enabled and the full 4 MB L3 cache.
According to Intel "Core i5 desktop processors and desktop boards typically do not support ECC memory", but information on limited ECC support in the Core i3 section also applies to Core i5 and i7.
Core i7
Intel Core i7 as an Intel brand name applies to several families of desktop and laptop 64-bit x86-64 processors using the Nehalem, Westmere, Sandy Bridge and Ivy Bridge microarchitectures. The Core i7 brand targets the business and high-end consumer markets for both desktop and laptop computers,and is distinguished from the Core i3 (entry-level consumer), Core i5 (mainstream consumer), and Xeon (server and workstation) brands.
Intel introduced the Core i7 name with the Bloomfield Quad-core processor in late 2008.In 2009 new Core i7 models based on the Lynnfield desktop quad-core processor and the Clarksfield quad-core mobile were added,and models based on the Arrandale dual-core mobile processor were added in January 2010. The first six-core processor in the Core lineup is the Gulftown, which was launched on March 16, 2010. Both the regular Core i7 and the Extreme Edition are advertised as five stars in the Intel Processor Rating. In January 2011, Intel released the second generation of Core i7 processors. Both the first and second generation of Intel Core i7 processors are rated as 5 stars in the Intel processor rating. The second generation of Intel core processors are based on the "Sandy Bridge" core and were updated in April 2012 with "Ivy Bridge".
In each of the first three microarchitecture generations of the brand, Core i7 has family members using two distinct system-level architectures, and therefore two distinct sockets (for example, LGA 1156 and LGA 1366 with Nehalem). In each generation, the highest-performing Core i7 processors use the same socket and QPI-based architecture as the low-end Xeon processors of that generation, while lower-performing Core i7 processors use the same socket and PCIe/DMI/FDI architecture as the Core i5.
"Core i7" is a successor to the Intel Core 2 brand.Intel representatives stated that the moniker Core i7 is meant to help consumers decide which processor to purchase as the newer Nehalem-based products are released in the future.
Sandy Bridge microarchitecture based
In early 2011, a new microarchitecture named Sandy Bridge microarchitecture was introduced; whilst keeping all the existing brands from Nehalem, including Core i3/i5/i7, it introduces new model numbers. The initial set of Sandy Bridge processors includes dual- and quad-core variants, all of which use a single 32 nm die for both the CPU and integrated GPU cores, unlike the earlier microarchitectures. All Core i3/i5/i7 processors with the Sandy Bridge microarchitecture have a four-digit model number. With the mobile version, the thermal design power can no longer be determined from a one- or two-letter suffix but is encoded into the CPU number. Starting with Sandy Bridge, Intel no longer distinguishes the code names of the processor based on number of cores, socket or intended usage; they all use the same code name as the microarchitecture itself.Ivy Bridge is the codename for Intel's 22 nm die shrink of the Sandy Bridge microarchitecture based on tri-gate ("3D") transistors, introduced in April 2012.
Core i3
Released on January 20, 2011, the Core i3-2xxx line of desktop and mobile processors is a direct replacement of the 2010 "Clarkdale" Core i3-5xx and "Arrandale" Core i3-3xxM models, based on the new microarchitecture. While they require new sockets and chipsets, the user-visible features of the Core i3 are largely unchanged, including the lack of support for Turbo Boost and AES-NI. Unlike the Sandy Bridge based Celeron and Pentium processors, the Core i3 line does support the new Advanced Vector Extensions.
The Ivy Bridge based Core-i3-3xxx line is a minor upgrade to 22 nm process technology and better graphics.
Core i5
In January 2011, Intel released new quad-core Core i5 processors based on the "Sandy Bridge" microarchitecture at CES 2011. New dual-core mobile processors and desktop processors arrived in February 2011.The Core i5-2xxx line of desktop processors are mostly quad-core chips, with the exception of the dual-core Core i5-2390T, and include integrated graphics, combining the key features of the earlier Core i5-6xx and Core i5-7xx lines. The suffix after the four-digit model number designates unlocked multiplier (K), low-power (S) and ultra-low-power (T).The desktop CPUs now all have four non-SMT cores (like the i5-750), with the exception of the i5-2390T. The DMI bus is running at 5 GT/s. The mobile Core i5-2xxxM processors are all dual-core chips like the previous Core i5-5xxM series and share most the features with that product line.
Core i7
The Core i7 brand remains the high-end for Intel's desktop and mobile processors, featuring the Sandy Bridge models with the largest amount of L3 cache and the highest clock frequency. Most of these models are very similar to their smaller Core i5 siblings. The quad-core mobile Core i7-2xxxQM/XM processors follow the previous "Clarksfield" Core i7-xxxQM/XM processors, but now also include integrated graphics.
Compiled by: Pee Ackun
Sources: Various
