What exactly is a CPU?

The fact, that the CPU is the processor of a computer or Mini-PC is most probably well known. But what tasks does it actually have and what is hidden behind the terms clock frequency, bus system and multi-threading?

CPU stands for “central processing unit“ and describes the processor of a computer. The “central” in CPU is not by chance since it can be seen as the heart of a computer. In addition to specific labels, the clock rate tells us how fast a processor is able to perform operations.

Tasks of the processor

On the whole a CPU assumes three essential tasks:

Arithmetical unit

All data on a computer consist of numbers. To be more precise: Of zeros and ones. A CPU accepts commands, calculates the appropriate amount of data and as a result gives out a new binary code. The higher the clock frequency of a CPU, the more digits can be processed simultaneously in an arithmetic operation. Clock frequency, which also can be described as a rhythm, is expressed in hertz. One Hz means one cycle per second. This means for a so-called single-core processor, that at one gigahertz (in short: GHz) approximately 1,000,000,000 digits can be processed at the same time.

Control unit

A control unit is together with the arithmetical unit a main component of a processor. In addition to the processing input and output peripherals (such as printers, scanners, mice, keyboards, …) the control unit ensures that the single components of a processor can work together appropriately and also coordinates them. The control unit and the other components of a CPU are connected over the so-called bus system.

Bus system

The bus system is a kind of bridge between the individual components of a computer and provides for the exchange of data between them.

Note: The more hertz a CPU got, the faster is the computing speed of a processor (of the same processor family). But is the clock frequency the only reason for the speed of a CPU? If today only the above mentioned single-core processors were still in use, we could answer the question quite easily with a “yes”. However, since two-core, four-core, six-core, eight-core and even ten-core processor are used in the field of desktops (as of 2016), the strength of a CPU also depends on the number of cores.

This brings us to the next subject:

Multi-core processors

As mentioned earlier CPUs have been made faster by increasing the number of clock rates. We remember: A single-core processor with one GHz is able to calculate 1,000,000,000 digits per second. Thus with two GHz it would be 2,000,000,000 digits per second.

However, the mere increase of the clock frequency implicates that enormous temperature rises will occur in the processor. This already happens at a power of 3,00 GHz. The reason behind this is that a higher clock rate can only be achieved by increasing the voltage. The resulting resistance in the thin leads produces heat. This is not only extremely inefficient but also damages the CPU without sufficient cooling. For this reason developers came up with the idea of installing several cores on one CPU. Today we are familiar with dual-core, quad-core, hexa-core, octa-core and also deca-cores processors.

A particularly great advantage of the so called multi-core processors is that the individual cores are able to assume tasks parallel to the other cores. Modern software, for instance, automatically stores operations on the individual cores of a processor in order to achieve an even utilization. If a core is fully utilized, the open tasks will automatically be transferred to a core with free capacities.

A further advantage is the low power consumption of the multi-core processors. Thus, a dual-core processor consumes only half as much energy compared to a single-core processor. The reason for this is that a dual-core processor with an equal performance as a single-core CPU requires a lower clock frequency due to a lower voltage. Ergo: Less power consumption.

Multi-Threading

Multi-threading is the ability of a single processor core to perform multiple tasks at the same time. Thus, multi-threading strongly resembles the appearance of a multi-core processor. In other words this means: If a quad-core processor is equipped with two threads per core, the system recognizes a total of eight virtual cores and no longer just four real cores. The advantage here is clearly obvious.

Conclusion

Single-core processors have lost a lot of importance in the fields of desktop computers and mobile areas and already have been banished by most sales shelves. This is also because extensive software in the user area requires at least two processor cores. This leads us to the question, what progress and how many cores the future will bring with it. Let’s wait and see!

More on this topic

15 Oct 2019 Array ( [id] => 463 [title] => What is the difference between mobile and desktop CPUs? [authorId] => [active] => 1 [shortDescription] => CPUs are not always the same. Depending on the device in which a processor is installed, different characteristics with regard to performance, power consumption or waste heat are important. Which types there are and what distinguishes them, will be clarified in this article. [description] =>

What is a desktop CPU?

A desktop CPU is, as the name suggests, usually built into a desktop PC. Therefore, heat development and power consumption play a minor role. On the one hand, there is enough room for fans and a cooling airflow, and on the other hand, there is no battery runtime that has to be taken into account, as desktop PCs are permanently connected to a power supply. In return, desktop processors offer good performance, a bigger cache and more turbo.

Intel desktop CPUs

The Intel Core i processors (e.g. i3/i5) comprise both mobile and desktop CPUs. These can be recognized by the one or two letters at the end of the product name. These include, for example:

  • K = can be overclocked (open at top)
  • S = energy savings through reduced performance (performance-optimized lifestyle), turbo mode is used less
  • T = power optimized lifestyle due to reduced equipment, often with fewer cores than the regular model
  • No letter = unspecified desktop CPU

An explanation of the structure of the processor names can be found at Intel.

AMD desktop CPUs

AMD uses entirely different names for its CPUs or APUs ("Accelerated Processing Unit" refers to a main processor with an integrated coprocessor – usually the GPU – which supports the main processor and can also be superior to him). The series carry certain names. Most of the desktop processor series also have a mobile variant, which then has the corresponding name. Among the current AMD desktop CPUs are:

  • AMD Ryzen = powerful processors of the so-called "zen architecture" for gaming and high end graphics, comparable to Intel Core i processors
  • AMD Athlon = multi-core processors with Radeon Vega graphics unit for the desktop as well as the mobile segment
  • AMD A series = entry-level processors with Radeon graphics unit
  • AMD FX series = multi-core processors designed for high-end applications, high overclocking is possible

What is a mobile CPU?

For mobile processors efficiency is more important than performance. The standing out feature is a low power consumption, since, for example, notebooks are not permanently connected to the power outlet and must therefore be able to run only with battery. In addition, they have less performance than desktop CPUs, because a lot of performance also means a lot of heat, and mobile devices offer little space for fans and heat loss. Nonetheless, thanks to modern technology, there are also mobile processors that are suitable for 4K gaming and other high-performance applications.

Intel Mobile CPUs

The Intel Mobile processors include the following series:

  • Intel Atom = range of microprocessors and system-on-chips (SoC) for low-cost and energy-efficient systems (also used in tablets, smartphones and infotainment systems in cars)
  • Intel Pentium = series of microprocessors and single-chip systems, more powerful than Atom

But even among the Celeron and Core-i CPUs there are mobile processors that are identified by the following letters, among others:

  • U = "ultra-low power", referred to CPUs with lowered voltage and TDP of about 15 W. They are mainly used in ultrabooks, where the power consumption plays a major role
  • Y = extremely low power, similar to U series, but TDP less than 13 W
  • M = mobile Dual-Core
  • QM = mobile Quad-Core
  • HQ = high performance graphics, quad core, especially for gaming laptops because of good performance, TDP around 45 W
  • HK = high performance graphics, unlocked similar to HQ, can be overclocked

AMD mobile CPUs

As mentioned earlier, most AMD product lines also have mobile variants:

  • AMD Ryzen Mobile = powerful APUs with Radeon Vega graphics unit
  • AMD Athlon = multi-core processors with Radeon graphics unit
  • AMD A-Series = for notebooks, suitable for gaming

Which CPU is suitable for what?

Typically, desktop CPUs are installed in desktop PCs, while mobile processors are used for notebooks, ultrabooks and Mini-PCs. However, as desktop CPUs are getting more and more power efficient, they are more and more being installed in laptops. In addition, the manufacturers also offer server and embedded CPUs. While the former are similar to the desktop CPUs, but offer even more power, the latter are characterized by their long-term availability.

Mini-PCs with desktop CPU

Due to their characteristics, Mini-PCs often incorporate mobile CPUs that consume much less power and generate less heat. However, many applications require good performance, so many spo-comm Mini-PCs are also equipped with desktop CPUs. These include the KUMO V and KUMO Ryzen models for high-end graphics applications, the rugged outdoor and vehicle PCs RUGGED GTX1050 Ti and RUGGED Ryzen, as well as a few models where the CPU is even freely selectable: CORE 2, NANO H310 and NOVA CUBE Q87.

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What is the difference between mobile and desktop CPUs?

CPUs are not always the same. Depending on the device in which a processor is installed, different characteristics with regard to performance, power consumption or waste heat are important. Which types there are and what distinguishes them, will be clarified in this article.
28 Jan 2020 Array ( [id] => 496 [title] => BGA, PGA and LGA – What is behind the different grid arrays? [authorId] => [active] => 1 [shortDescription] => If you take a closer look at different CPU types, you will inevitably come across terms such as BGA, PGA and LGA. We will explain to you what these abbreviations actually mean. [description] =>

The terms BGA, PGA, LGA and CCGA are name types of integrated circuit packaging. However, they differ in the type of connections.

Ball Grid Array (BGA)

The abbreviation BGA stands for "Ball Grid Array". In this package, small solder balls form the connections, which are arranged in a square grid made up of columns and rows on the bottom surface of the chip. This design enables considerably more connections to be accommodated, roughly twice as many as with PGA. The solder balls provide short connections and therefore an enormous performance.

The advantages of BGA lie in the small space requirement, the good heat dissipation and the low impedance due to short connection paths to the circuit board. In addition, the chips can be unsoldered from the circuit board without damaging them. This enables the removal of old solder balls (deballing) and populating with new balls (reballing). The chip can then be soldered to a new circuit board. Since soldered processors are mechanically and thermally extremely robust, BGA is mainly used for embedded CPUs.

A major disadvantage is that the solder joints can only be checked by X-ray, as the connections are covered and difficult to access. This also severely limits repair options. Special equipment, a so-called reflow oven, is required for safe soldering. In addition, BGA chips can only be used effectively on multilayer boards, which limits their application possibilities.

Pin Grid Array (PGA)

The so-called "Pin Grid Array" (PGA) is mainly used for processors. While soldering balls are used with BGA, the pin grid array - as the name suggests - uses small pins as connections. These are also arranged in a square grid, but the number of connections and arrangement of the arrays varies, so that there is a large number of variants and thus different CPU sockets. The rows of pens can be arranged in parallel or offset, they are identified with numbers and letters.

There are different types of PGA:

  • With the Ceramic Pin Grid Array (CPGA), the semiconductor chip is fixed on a heat-conducting ceramic carrier. It is used in the first generation Intel Pentium, socket A variants of the AMD Athlon and the Duron family.
  • With the Plastic Pin Grid Array (PPGA), the carrier for the semiconductor chip is made of plastic. This variant is a little cheaper, has better thermal properties and also an improved electrical performance than ceramics. PPGA is mainly used for the Pentium MMX processors and Celeron.
  • The Staggered Pin Grid Array (SPGA) is characterized by staggered connection rows. This variant is required for CPUs that have more than 200 connections, because the offset layout offers more space. It is used on the Pentium and later central processing units.
  • With the Flip-Chip Pin Grid Array (FCPGA), the integrated circuit is attached to the top of the carrier ("flip-chip" means "inverted, turned chip"). This design is used for example in Pentium III and some Celeron processors.

Since the pins for PGA are on the CPU, the corresponding holes are on the mainboard so that the CPU can be installed without much pressure.

Land Grid Array (LGA)

The Land Grid Array (LGA) is the exact opposite of PGA. The contact pins are on the base of the mainboard. The CPU has the same number of contact points with which a connection is established. Intel has been using LGA for the majority of its Celeron, Pentium, Core and Xeon CPUs for many years.

The advantages of LGA are, on the one hand, the smaller size of the pins, which enables a larger number of pins in the same area. Secondly, they are not easily damaged because the socket has no pins that can be crushed. Compared to LGA, PGA sockets have the advantage that the mainboard cannot actually be damaged. In addition, pins are easier to repair on a PGA processor than on a LGA mainboard.

Ceramic Column Grid Array (CCGA)

Even if it has nothing to do with Mini-PCs, we want to mention the Ceramic Column Grid Array (CCGA) here for the sake of completeness. CCGA housings are extremely reliable and are used in space and military technology. The solder connections on the underside of the housing are columnar (hence the name “column”) and consist of heavily leaded solder. Similar to BGA, the columns are arranged in a grid. They cannot be used in the civilian market because they are not permitted under the RoHS guidelines due to the high lead content due to EU trade bans.

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BGA, PGA and LGA – What is behind the different grid arrays?

If you take a closer look at different CPU types, you will inevitably come across terms such as BGA, PGA and LGA. We will explain to you what these abbreviations actually mean.
25 Feb 2020 Array ( [id] => 502 [title] => What is an Embedded-CPU? [authorId] => [active] => 1 [shortDescription] => After we recently explained the difference between mobile and desktop CPUs, we would now like to go into a third type: the embedded CPUs. [description] =>

What does "embedded" mean?

An embedded system is a computer that is integrated in a technical environment and takes over tasks such as monitoring, control or data processing. These include, for instance, small computers in washing machines, televisions, routers, refrigerators or cars. However, we are now talking about somewhat larger systems: Embedded PCs that are equipped with a corresponding CPU.

Where are embedded CPUs used?

Embedded CPUs are mainly used in the professional environment, for example for industrial applications, in vehicles or in medical technology.

What are the advantages of an embedded CPU?

The CPUs are characterized by increased reliability, an extended temperature range and above all by a long component availability. For example, Intel guarantees long-term availability of up to 15 years for its embedded processors. The advantage of this: once an application is running, its use is secured for the next few years and the developers do not have to adapt the hardware and software again after a short time. In addition, embedded systems are often certified. If the CPUs are available for many years, there is no need for expensive re-certifications.

Another advantage is that embedded CPUs are extremely robust, since they are usually soldered processors with BGA (Ball Grid Array), which bring a high level of mechanical and thermal robustness with them. This means, that Embedded PCs can run 24/7 in harsh environments without problems. Thanks to their compact design, embedded CPUs are made for Mini-PCs and score with low power consumption.

What are the disadvantages of an embedded CPU?

With all the advantages, the question arises whether an embedded CPU has any negative properties. In fact, we can only mention the low performance here, since, as with mobile CPUs, not much can be accommodated in a small space. However, a lot has happened here in recent years. And it is always enough for the areas in which embedded CPUs are mainly used.

Intel and AMD embedded CPUs

Both major processor manufacturers have various models on offer: Intel has embedded CPUs in the Celeron, Pentium and Core i3 series. AMD offers the Ryzen Embedded and Epyc Embedded series.

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What is an Embedded-CPU?

After we recently explained the difference between mobile and desktop CPUs, we would now like to go into a third type: the embedded CPUs.