Microprocessors Chapter 3

Overview In this chapter, you will learn how to Identify the core components of a CPU Explain the varieties of modern CPUs Identify specialty CPUs Install and upgrade CPUs Instructor Tip When gaining attention and establishing common ground, ask questions of the class such as, “Who here has ever seen a CPU?” or “Who here has ever installed a CPU?” For a positive statement, tell the class, “In this lesson, we will learn how to recognize various CPUs and upgrade a computer CPU.”

CPU Core Components Discussion Point ESD Recall from the first lesson in Chapter 2, the issues concerned with electrostatic discharge (ESD) and the precautions to be taken when handling components. Try to reinforce this concern throughout the coursework.

Concepts Microprocessor and CPU (Central Processing Unit) mean the same thing CPU’s are not very smart…just very fast at manipulating 0s and 1s

Man in the Box Visualize the CPU as a man in a box. He will gladly perform anything you want him to, but he can’t see or hear anything outside the box. How can we communicate with him?

Talking to the Man Suppose we have 16 lights – 8 on the inside and 8 on the outside When an inside light is on, the corresponding outside light is on. We can switch these lights on and off. This communication system is like the external data bus

Talking to the Man In reality there are a lot of little wires that flash on or off by applying a voltage or not – represented not as on, on,off,off… but as 1,1,0,0…

External Data Bus The external data bus (EDB) is the way the CPU communicates with the outside world Instead of light bulbs the external data bus (EDB) is made up of tiny wires The state of a wire is expressed in a binary format, with 0s and 1s Each discrete setting (series of 0s and 1s representing the state of the wires) of the external data bus is a line of code in a program

Clock The CPU does no work until told to – even though all the light bulbs may be ready You need a buzzer to tell the guy to go ahead – the time it takes to charge up the buzzer (give it a certain voltage) to make it go off is a clock cycle Commands require from two to hundreds of clock cycles to be processed. CPU makers sell the exact make and model of CPU at a number of different speeds. All of these CPUs come off of the same assembly lines, so why different speeds? Every CPU comes with subtle differences—flaws, really—in the silicon that makes one CPU run faster than another. The speed difference comes from testing each CPU to see what speed it can handle.

Clock The crank of the CPU is a special wire called the clock A clock cycle is the time taken by the special wire to charge up The CPU needs at least two clock cycles to act on each command The maximum number of clock cycles that can be handled by the CPU is called the clock speed The Intel 8088 ran at 4.77 MHz (4.77 million cycles per second). Today’s CPUs run at several Gigahertz.

In Summary The Man in the Box is the CPU He communicates with the outside world using light bulbs – which in reality is a set of wires called the external data bus

CPU Video Summary http://www.youtube.com/watch?v=0mvKz_tmcmU Watch this video: http://www.youtube.com/watch?v=0mvKz_tmcmU

Defining CPUs There are four main things to describe and compare CPUs: Make Intel or AMD Model 486DX2, Pentium, Pentium Pro, Athlon Speed Measured in MHz or GHz such as 266 MHz or 1.4 GHz How it’s mounted Slotted or socketed Neither VIA nor Transmeta CPUs show up on the A+ Certification exams. AMD CPUs and sockets are totally different than Intel CPUs and sockets so we often use the name of the socket instead of the model. For example: “Hey, is that a Socket A motherboard?”

Common CPU Packages Staggered Pin Grid Array (SPGA) Pins are staggered and more closely packed to keep the overall size of the package small Pentium, Pentium Pro, K5, K6, 6x86 Common CPU Packages that are no longer used: Dual Inline Pin Package (DIPP) - First generation package for microprocessors. Two rows of pins on each side. Obsolete now - 8088, 8086, 80286 Pin Grid Array (PGA) - Popular package for desktop machines as they are relatively larger in size and enable easy heat dissipation. Pins are on the bottom of the chip. Obsolete now – 80286, 80386, 486 Plastic/Ceramic Quad Flat Pack (PQFP/CQFP) Primarily used on laptop machines. Obsolete – 80286, 80386, 486 Plastic /Ceramic Leaderless Chip Carrier (PLCC/CLCC) - Used on machines which are designed for upgradibility. Obsolete – 80286, 80386

Common CPU Packages Single Edge Contact Cartridge (SECC) Take up less space and enable better cooling of the CPU. Obsolete – Celeron, Pentium II, Pentium III, Athlon Other common CPU packages include: Plastic Pin Grid Array (PPGA) - Built using high-thermal plastics. Pentium, Celeron, Athlon, Duron Flip-Chip Pin Grid Array (FC-PGA) - Improved the wiring process of the CPU Ball-Grid Array (BGA) - Used tiny balls instead of typical pins

Multiprocessing Multiprocessing is running two programs at the same time Pentium processors have a 32-wire address bus that can address up to 232 or about four gigabytes of memory Actually CPUs do not run two programs at once. They simply switch back-and-forth between them so that it looks like they are doing two things at once. Tech Tip Multiprocessing, Multiple Processors, What Gives! Don’t confuse “multiprocessing” with “multiple processors.” The nomenclature is a bit confusing here—all the term “multiprocessing” means is that the CPU can handle “multiple processes,” or programs, at one time. Multiprocessing does not mean that the CPU can be used in system with other CPUs, like in large-scale servers, which sometimes have two, four, or even eight CPUs total! Modern multiprocessor support was first introduced with the Intel 80386 CPU.

Cache Cache means to set aside data in a special, fast storage area Disk cache is moving data between mass storage and RAM RAM cache is moving data between RAM and the CPU Discussion Point Cache Cache means to put something aside for later use. In computing, it means the CPU puts aside common instructions into a holding area made up of a fast kind of memory called SRAM. Since SRAM is much faster than DRAM, the CPU may access the instructions from the cache much faster than it can get it from DRAM or from slow storage devices. The purpose of caching is to eliminate bottlenecks such as those created when the fast CPU secures data or instructions from slow storage devices or DRAM. Computers have two kinds of caches to handle these two bottlenecks. The disk cache is used to move data between mass storage devices and RAM while the RAM cache moves data from RAM to the CPU. A disk cache may be either hardware or software or a combination of the two. A RAM cache involves hardware, specifically fast SRAM.

Mobile Processors Mobile processors For laptops Overcome the problems of heat and size

Mobile Processors Laptops require CPUs that are smaller, use less power, and run cooler AMD and Intel make mobile versions of all of their CPUs Intel introduced the mobile module that includes the processor and support chips to conserve space System Management Mode (SMM) is used to reduce power consumption on laptops SMM is the CPU side of power management. SMM works with software standards such as APM (Advanced Power Management) and ACPI (Advanced Configuration and Power Interface).

Installing CPUs

Why Replace a CPU? Cost Cooling Performance Chances are you’ll need to replace the motherboard as well as the CPU – is it worth it? Cooling Faster CPUs will probably need better cooling Performance Faster CPUs may not be the best answer to speeding up your PC Many times what you really need is more RAM Before attempting to do anything inside the system unit, make sure you have adequate ESD protection. Make sure the power is off and the system is unplugged. Many motherboards have no jumpers or switches.

The Right CPU Consult your motherboard manual Buying a CPU You need a CPU that will fit in the socket or slot you have on your motherboard Buying a CPU Most stores will not accept returns Retail-boxed CPUs are genuine and come with a fan There are a lot of illegal CPUs on the market Tech Tip Motherboard Book Versus Instruction Manual Don’t confuse the motherboard book with the instruction manual or user’s guide that comes with many OEM systems. The user’s guide describes only issues like opening the system unit and inserting a keyboard—it won’t help with more complex issues like motherboard-CPU compatibility. If you can’t find a motherboard book for your system, odds are good that either the motherboard book is lost, or you never got one in the first place. Most OEMs (Dell, Gateway, IBM, and so on) do not provide a motherboard book with their systems.

CPU Installation Guidelines Don’t touch the pins Match the notch and dot printed on the corners of the CPU…it must line up Incorrectly installing your CPU may destroy the CPU and/or motherboard! Zero Insertion Force (ZIF) Sockets make installation of CPUs much easier today. Discussion Point Aligning the CPU to the Socket If pin 1 of the CPU is not aligned to pin 1 of the socket, it can destroy the CPU and/or damage the socket itself. You can identify pin 1 by its clipped corner or by a dot on the corner. Similarly, the socket itself will have a clipped corner identifying pin 1. On older CPUs without a corner clipped or a dot on the corner, note the underside of the CPU. Pin 1 has a square solder base while all the other pins have round solder bases. That square pin is oriented to the clipped corner of the socket. (The square solder pad also identifies pin 1 on all other kinds of chips or boards.)

CPU Installation Guidelines Install a fan on top of the CPU after the CPU has been inserted into the socket Use a heat sink compound Heat Sink Compound Use a small amount of heat sink compound (white paste) – many fans come with compound already on them but covered with a small square of tape that needs to be removed You will need to use a little force to snap the fan in place The fan will require a power connection

Plugging in the CPU Fan

The Art of Cooling Modern CPUs need to be kept cool OEM fans are included in retail-boxed CPUs Liquid cooling works by running a liquid (usually water) through a metal block that sits on top of your CPU to absorb heat OEM means “original equipment manufacturer”. Specialized fans are sold by third-party companies.

Overclocking Overclocking is running a CPU at a speed higher than rated Voids the warranty Black market exists Check your CPU speed with the Intel Processing Frequency ID utility available from Intel for free: http://support.intel.com