Beginners: Understanding processors

The processor is always the most stressed component on any PC. When buying a desktop or notebook, almost always the first information given is the model and / or processor clock.Besides being in charge of processing the most information, the processor is the component where the technologies are used to manufacture the latest.

The world has only three companies with technology to produce competitive processors for personal computers PC: Intel, AMD and VIA. We used to have other manufacturers such as IDT (IDT who made the C6, competing with the Pentium), Texas Instruments (which manufactured chips 386 and 486), Cyrix (which was acquired by VIA), Transmeta (Crusoe manufacturer) and even IBM. However, over time all have been pushed up out of the market, leaving Intel and AMD fighting for supremacy and a small VIA struggling to survive.

In the PC world, it all began with the 8088, released by Intel in 1979 and first used in the PC launched by IBM in 1981. Then came the 286, launched in 1982, and 386, released in 1985.

The 386 can be considered the first modern processor, it was the first to include the x86 instruction set basics, used until the present day. The 486, which is still part of the memories of many people bought their first computer during the 1990s, was released in 1989, but was still common to find computers with it for sale until about 1997.

After we entered the current era, inaugurated by the Pentium, which was launched in 1993, but it took several years to become popular and replace the 486. In 1997 it launched the Pentium MMX, which was one last breath to the platform. Then in 1997 came the Pentium II, which used a different fit and was therefore incompatible with older motherboards. AMD took advantage of the opportunity, developing the K6-2, a chip with an architecture similar to the Pentium II, but that was compatible with the older Socket 7 boards.

From there things began to happen faster. In 1999 it launched the Pentium III and in 2000 thePentium 4, which brought an architecture very different from previous chips, optimized to allow the release of processors working at higher frequencies.

The latest Pentium III working at 1.0 GHz, while the Pentium 4 was quickly the 2.0 GHz, after 3 GHz 3.5 GHz and then the problem is that the Pentium 4 had a performance per clock cycle than other processors, which makes that the high frequency of operation would serve simply to balance things. The first version of the Pentium 4 processor operating at 1.3 GHz and still lost to the Pentium III 1.0 GHz in several applications.

The higher the processor frequency, the more energy it consumes, and thus more heat is dissipated by him (as the first law of thermodynamics, "nothing is lost, everything becomes").The heat was not a prolema at the time the Pentium 1, when the processors used only 10 or 15 watts, but is a major limiting today, where many processors break the mark of 150 watts.

It is not uncommon for domestic processors are able to operate at twice the nominal frequency when cooled with liquid helium or nitrogen (the record for the Phenom 45 nm, for example, is 6.5 GHz), which eliminates the problem of temperature. However, when using a regular cooler, the temperature becomes a limiting long before.

When the possibilities of increasing the clock ran out Pentium 4, Intel launched the Pentium D,a dual-core version of Pentium 4. Initially the Pentium D were expensive, but with the launch of Core 2 Duo they are cheaper and are now used even in low-cost PCs. The Pentium D was sold under a numbering system and not under the actual clock frequency. The Pentium D 820, for example, operates at 2.8 GHz, while the 840 operates at 3.2 GHz

In 2003 Intel introduced the Pentium M, a chip derived from the ancient architecture of the Pentium III, which consumes less energy, heats up a little and still offers excellent performance. A Pentium M 1.4 GHz reached overcome a Pentium 4 2.6 GHz in several applications.

The Pentium M was originally developed for use in notebooks, but proved so effective that was eventually used as the basis for the development of the Core platform, used on Intel Core 2 Duo and Core 2 Quad. The Pentium 4 turned out to be a dead end, discontinued and doomed to oblivion.

Parallel to all these processors, we have the Celeron, a cheaper version, but with a slightly lower performance, as they have less cache or other limitations. Actually, the Celeron is not a separate family of chips, but only a brand name used in the cheaper versions (with half or a quarter of the cache) for various Intel processors. There Celerons based on the Pentium II, Pentium III, Pentium 4, Pentium M and even the Celeron E1xx, which is a version with less cache Core 2 Duo

For comparison between the old and the chips today, a 486 was about 1.2 million transistors and even 133 MHz, while the Pentium MMX was 4.3 million and reached a 233 MHz Pentium 4 (Prescott) has 125 million and came to 3.8 GHz, which was for many years the frequency of higher clock used by an x86 processor.

The transistor is the basic unit of processor capable of processing one bit at a time. More transistors allow the processor to process more instructions at a time while the frequency of operation determines how many CPU cycles are performed per second.

The use of more transistors allow the processor to include more components (more cores, execution units, more cache, etc.). And do more processing per clock cycle, while the frequency of operation determines how many CPU cycles are performed per second. You can increase the processor performance by increasing both the number of transistors and increasing the frequency, but as both approaches have their limits, manufacturers are required to find the best combination of both.

Below, we have the AMD processors. She began producing clones of processors 386 and 486, very similar to Intel's, but cheaper. When Intel launched the Pentium, which required the use of new cards, AMD launched the "5 × 86", a 486 to 133 MHz, which was very popular, serving as a cheap option to upgrade.

Although the "5 × 86" and 133-MHz clock gave the impression that this was a processor with a similar performance to a Pentium 133, the performance was much lower, barely competing with a Pentium 66. This was the first of a series of examples, from both AMD's and Intel's side, where there was an obvious difference between the performance of two processors on the same clock. Although it is an important item, the frequency of operation is not a direct indicator of processor performance.

An analogy could be made in respect of motor cars. The engines of 1.6 in the late 70's, used in Brazil and the Beetles had 44 horsepower, while the current 1.0 engine reach more than 70 horses. In addition to the cubic capacity, there are many other factors, such as the efficiency of the injection of air and fuel, compression, refrigeration, etc.. the same applies to processors, where we have the number of execution units, the hit rate of branch prediction circuit, the size and efficiency of the caches and so on.

Further, after 5 × 68 AMD released the K5, a processor similar to the Pentium, but that was not as successful. He was followed by the K6 and later the K6-2, which again was quite successful, served as an option for low cost processor and at the same time, as an upgrade option for someone with a Pentium or Pentium MMX.

This was the K6-2 was the dark ages of computing, not by the CPU itself (except that the performance in games, had a cost-effective), but the cheaper motherboards that have flooded the market.

Taking advantage of the low-cost processor, manufacturers will develop boards increasingly cheap (and increasingly poor quality) to sell more by offering low-cost PCs. The era was marked by aberrations. A certain manufacturer has come to launch a family of cards without L2 cache, which capacitors emissions (leading to the end of life of the board) after only one year of use.

Things back on track with the Athlon, which became the most successful architecture of AMD.The first version used a paper cartridge (slot A) similar to the Pentium II, but incompatible with the plates for him. He was succeeded by Athlon Thunderbird, now use the format of socket used (with updates) until the present day

Competing with the Celeron, AMD Duron produced, a low cost processor, identical to the Athlon, but with less cache. In 2005, the Athlon was discontinued and the office was passed by the Sempron, an improved version of Duron (with more cache and capable of higher frequencies), which went on sale a second performance index (compared to Pentium 4) and not over the second clock rate.

Around 2000 came the first news of the "SledgeHammer, a processor 64-bit, which was finally released on the way home version of the Athlon 64, which became the top line of AMD. Despite internal changes, the Athlon 64 is still compatible with 32-bit programs, the same as the current processors are capable of running software on the time of 386, even though they have incorporated several new features.

In practice, the fact that a 64-bit processor does not make the Athlon 64 screamingly fast, even in optimized applications (performance gains arise more due to the integrated memory controller and new registrars). The main advantage of 64-bit processors is to overthrow a limitation inherent to all 32-bit processors, which are able to access only 4 GB of RAM, a limit that is becoming an increasingly serious constraint in many areas.

The Athlon 64 has led to the Athlon X2, the first dual-core processor from AMD, where we have two Athlon 64 processors in the same package, sharing the processing load and also to the various versions of the Athlon boards for socket 754, AM2 and AM3, which became quite popular in low-cost PCs.
With the advance of the Core 2 Duo, AMD was quick to update the architecture of the Athlon 64, including some improvements in architecture and (more importantly) support the use of 4 cores and shared L3 cache. Then came the Phenom, which was the first quad-core AMD home.

The Phenom has been produced in several variations, including versions with three cores (Phenom X3), with two cores (Phenom X2) and also versions with the cache disabled. They arose from the need to maximize the volume of production, making the processors with defects located in low-cost versions. The former gave rise to the Sempron Athlon X2 II, a low-cost version of the Phenom, which maintains the same architecture, but excludes the shared L3 cache.

Initial versions of the Phenom were produced using a technique of 65 nanometers (similar to that used by Intel to produce the initial version of the Core 2 Duo), which limited the size of L3 cache. In 2009, AMD switched their factories to the technique of 45 nm, which gave rise to thePhenom, which brought 6 MB of L3 cache. With the new manufacturing technique, Athlon II has also been upgraded and is now sold in two versions with cores (Athlon X2 II) and 4-core (Athlon X4).

The latest round began with the launch of Core i7 and Core i5, which inaugurated the new generation of Intel processors, feeding the cycle of releases. One of the changes introduced by them was the Turbo Boost, a management system that increases the clock frequency of the processor when only some of the core is being used, functioning as a sort of automatic overclocking system. He made the performance of processors much more variable, as it now also depend on the operating temperature of the processor and other factors.