3.9.1 Processor Concepts.txt

IndicatorProcessor Concepts 0:00-1:43 In this lesson, we’re going to spend some time discussing the brains of any computer system, and that’s the central processing unit, which we call the CPU, or processor. Let’s begin this lesson by discussing the role and function of the CPU. The CPU is an integr...

IndicatorProcessor Concepts 0:00-1:43 In this lesson, we’re going to spend some time discussing the brains of any computer system, and that’s the central processing unit, which we call the CPU, or processor. Let’s begin this lesson by discussing the role and function of the CPU. The CPU is an integrated circuit and contains millions of microscopic circuits called logic gates. They’re all connected by hairline strands of aluminum that work together to store and manipulate data. A CPU can accept instructions, or programs, and execute those instructions to perform both arithmetic and logical operations. These instructions may tell the CPU to perform tasks. It could prompt the user to enter a series of numbers, read the input from the system keyboard as the user types them, store those numbers in specific memory locations in the system RAM, use arithmetic functions to add all those numbers together and then write the result to a new location in the system RAM, write a message on the screen explaining the result and then open a file on the hard drive and write the result to that file, or to save the file and then close it. So, when we say the CPU is the brains of the computer, we really aren’t kidding. Without a CPU, none of the other components in the system would be able to do anything. The CPU connects to the rest of the system using a special socket on the motherboard. This socket contains a series of many small connectors into which you plug the CPU. And by doing this, electric connections are established with the motherboard bus, which, in turn, connects the CPU to other components in your system, like the system RAM, your storage devices, your video interface, and other expansion cards that are installed in the expansion slots. You also need to be familiar with the CPU’s clock speed. Clock Speed 1:43-2:26 The clock speed identifies the rate at which the CPU can execute instructions. The clock speed is measured in gigahertz. The CPU requires a fixed number of clock ticks to execute each instruction. Generally speaking, the faster the CPU’s clock speed, the more instructions it can execute per second. The clock speed is very important. Understand that for all the components connected to the motherboard to communicate with each other, such as the RAM, the CPU, and the expansion cards, the components must be synchronized to the same clock. Therefore, your CPU’s clock speed must be supported by the motherboard, and vice versa. With that in mind, we need to talk about overclocking. Beware that, with most systems, the CPU, the RAM, and the motherboard can be overclocked to a degree. Overclocking 2:25-3:26 Overclocking is pushing a CPU beyond its designed specifications. You can gain a marginal increase in performance by doing this. Intel’s Turbo Boost technology allows the processor to dynamically run above its rated speed. It also allows a CPU to overclock as needed. Overclocking basically increases the speed that the clock runs. Because the clock runs faster, the CPU, the memory, and the motherboard all run faster too. In theory, this provides better performance. However, beware that the improved performance comes at a price. Overclocked systems tend to run much hotter and consume more electricity. And the increased temperature can significantly reduce the lifespan of the CPU, as well as the other components in the system. In addition, if you push the CPU too fast, you’ll probably experience system instability. So you must decide whether the increased performance is worth the shortened lifespan of the device, as well as the potential instability of the system overall. With that in mind, let’s shift gears and talk about CPU cache memory. Cache Memory 3:25-3:56 The important thing to understand here is that the CPU has its own built-in memory. We call it the CPU cache. CPU cache is different from the system RAM. The CPU cache is made up of static random access memory chips, or SRAM, which are very fast. In fact, they’re much faster than the DRAM chips that system RAM chips are made from. The CPU cache is used to store a copy of frequently accessed information from the system RAM. This can significantly increase performance. Now let’s talk about the concept of a core. Multi-Core Processors 3:56-4:46 In early CPUs, there was one processor within each CPU package. In other words, it only had a single core. If you wanted really great performance from a computer system, you could purchase a special motherboard that had two or more CPU sockets, allowing you to implement multiple CPUs at the same time. Today, however, most CPUs have multiple processors, or cores, within the same CPU package. Implementing multiple cores dramatically improves the system performance. The key thing to remember is that a multi-core CPU can execute more than one instruction at a time. For example, if you have four cores within your CPU, each core can execute an instruction concurrently. So, instead of processing just one single instruction, the CPU can execute four instructions at the same time. In addition to multiple cores, some CPUs also support multi-threading. Multithreading 4:45-5:09 Multithreading allows a single core within a CPU to execute two instructions at the same time. Multithreading can also increase system performance, especially if it’s implemented within a multi-core CPU. For example, if you have a CPU that has four cores and each one of those cores is a multithreading core, that CPU can run eight instructions concurrently. Some CPUs also support hyper-threading. Hyper-Threading 5:09-5:54 In 2002, Intel introduced the hyper-threading technology. This technology is owned by Intel. Hyper-threading is a form of simultaneous multithreading technology. With hyper-threading, one physical core appears to the operating system as two processors. This allows one core to process two instructions at the same time. The two processes can also use the same resources, so if resources for one process aren’t available, then another process can continue if its resources are available. Hyper-threading gives you about a 20 percent increase in performance. Hyper-threading is not to be confused with multi-core or multithreading technology. There’s always a wide variety of CPUs available to you, and some are better for creating graphics, crunching numbers, playing games, and so on. Integrated GPU 5:49-6:18 A GPU, or graphics processing unit, is a programmable logic processor specialized for display functions. The GPU renders images, animations, and video for the computer’s screen. GPUs are located on plug-in cards, in a chipset on the motherboard, or in the same chip as the CPU. If it’s on the same chip as the CPU, it’s called an integrated GPU. Let’s discuss virtualization technology. Virtualization 6:18-7:11 Virtualization is the ability to install and run multiple operating systems simultaneously on a single physical machine. Let’s say we have a data center with four servers and four physical platforms, each running an application. There’s a database server, an application server, an email server, and a file server. Now, suppose we combine these services virtually onto one server platform. These servers still exist, but they exist as virtual machines running under a single host OS on a single hardware platform. That’s the concept of virtualization. The virtual machines appear as self-contained and separate physical systems. Each virtual machine looks and acts like a traditional computer system. If your computer will be used as a virtualization system, then you need to make sure that the CPU you want to implement supports virtualization. Now, let’s discuss cooling. Cooling 7:10-9:36 When you work with modern CPUs, you have to keep cooling foremost in your mind. Sometimes people turn their systems on for testing purposes without the CPU cooler installed. This is a bad idea because modern CPUs generate a lot of heat. Heat is bad for your computer systems. An uncooled CPU will burn up in less than a minute. CPUs use a heat sink, fan, thermal paste, liquid, or fanless cooling system to transfer heat from the CPU to the cooling unit. Install a heat sink and fan before you ever turn the system on. There are several different CPU cooling options available. The first one is to use a heatsink. This can be a more passive form of CPU cooling. The heatsink makes physical contact with the CPU, which, essentially, increases the CPU’s surface area, allowing more heat to be dissipated. A heatsink alone can’t adequately cool a CPU. If you’re going to use a heatsink, then you should always use it in conjunction with a fan. The fan blows air over the heatsink to increase the airflow. By doing this, we remove more heat from the heatsink more quickly. This is an example of active cooling. Another option available is to use heat pipes. Heat pipes are usually implemented in conjunction with a heat sink. The heat pipes are filled with a liquid that absorbs heat from the CPU. As they do, liquids within the pipe evaporate. Because that vapor is less dense than the liquid around it, it rises towards the heat sink on the other end of the heat pipe. Then the heat sink and a fan cool the vapor, causing it to condense back into a liquid. When it does, it drops back down to the CPU, on the other end of the heat pipe. The system keeps cycling that way to remove heat from the CPU. This system is usually much more efficient at cooling the CPU than the traditional heat sink and fan, and it’s a good example of active cooling. There’s a fourth option available that’s more expensive and not as widely implemented, the radiator. This option uses a coolant, a fan, a pump, and a radiator, much like your car’s cooling system. The coolant cycles through the system, exchanging heat from the CPU to the radiator, where it’s dissipated by the fan. No matter which cooling option you use, you need to make sure that you use thermal paste. Thermal paste is critical because it facilitates heat transfer from the CPU to the CPU cooler. With all of this information in mind, let’s end this lesson by discussing several key criteria to remember when you’re selecting an appropriate CPU in a new implementation. Select A CPU 9:29-11:10 First, you need to identify the purpose of the system. You need to be sure that the CPU you select can perform the task that you want the system to perform. Also, you need to make sure that the CPU is supported by the motherboard. Two considerations need to be taken into account. First of all, is the CPU compatible with the socket on the motherboard? And second, will the motherboard’s BIOS or UEFI firmware support that CPU? A CPU may fit into the socket, but that doesn’t mean the motherboard itself will support it. You also need to identify the appropriate CPU speed. However, don’t rely solely on the CPU’s clock speeds when you’re making comparisons between processors. There are many other factors that need to be taken into account, such as the CPU architecture, the number of cores, whether multi-threading is supported, and the amount of cache memory that has been implemented with the CPU. One way to get around this is to use websites, such as cpubenchmark.net. These websites objectively assign a benchmark score to your CPUs that allows you to compare to see which one is fastest. You also need to take cost into account when you’re selecting a CPU. You need to decide how much performance you need versus how much money you’re willing to spend. Generally speaking, CPUs that are manufactured by Intel tend to provide the best performance. But they also come at a premium price. CPUs manufactured by AMD, on the other hand, tend to be much less expensive, but they also don’t perform quite as well. So you must make that choice between cost and performance. That’s it for this lesson. Summary 11:11-11:24 In this lesson, we introduced you to the CPU. We talked about the role and function of the CPU, clock speeds, overclocking, cache memory, multi-cores, multithreading, and hyper-threading. Then we talked about virtualization, cooling, and the factors you should keep in mind when selecting a CPU.