• Choose a category
• All
• Classic-Fiction

By Root 1247 0

over the years for hundreds of CPU models with such names as staggered-PGA, micro-PGA, ball grid array (which uses tiny balls instead of pins), and land grid array (which uses flat pads instead of pins). Other varieties of PGA CPUs are based on the number of pins sticking out of the CPU. The CPUs snap into special sockets on the motherboard, with each socket designed to match the pins (or balls or pads) on the CPU. To make CPU insertion and removal easier, these sockets—officially called zero insertion force (ZIF) sockets—use a small arm on the side of the socket (Figure 5-23) or a cage that fits over the socket (Figure 5-24) to hold the CPU in place. ZIF sockets are universal and easily identified by their squarish shape.

* * *

NOTE Although there are many types of PGA packages, most techs just call them all “PGA.”

Figure 5-23 ZIF socket with arm on side

Figure 5-24 ZIF socket with cage over the top

The first generations of sockets used a numbering system that started with Socket 1 and went through Socket 8. Because of the hassle of trying to remember how many pins went with each type of socket, CPU makers started giving all sockets a name based on the number of pins. Most sockets today have names like Socket 1366 and Socket 775 to reflect the number of pins.

* * *

NOTE AMD CPUs and sockets have totally different numbering systems than Intel CPUs and sockets, so techs often use the name of the socket instead of AMD or Intel. For example: “Hey, did you see that Socket 1366 motherboard?”

It’s very important to know the more common CPU/socket types. As you go through each type of CPU in this chapter, pay attention to the socket types used by those particular CPUs.

The Pentium CPU: The Early Years

Since the advent of the 8088 way back in the late 1970s, CPU makers have made many improvements. As technology has progressed from the 8088 to the most current CPUs, the sizes of the external data bus, address bus, and registers have grown dramatically. The clock speeds at which CPUs run have kept pace, getting faster and faster with each successive generation of processor. The 1980s were an exciting time for CPU technology. The 8088 CPU was supplanted by a series of improved processors with names such as 80286, 80386, and 80486 (Figure 5-25). These CPU families incorporated wider buses, increasingly higher clock speeds, and other improvements.

Figure 5-25 Old CPUs

In the early 1990s, Intel unveiled the Pentium CPU. Although no longer manufactured, the original Pentium CPU was the first Intel CPU to contain all of the core functions that define today’s modern CPUs.

* * *

NOTE Many of the CPU features attributed here to the Pentium actually appeared earlier, but the Pentium was the first CPU to have all of these features.

The Pentium retained the core features of the 8088 and subsequent processors, although the clock was much faster, the address bus and external data bus were wider, and the registers had more bits. You’ll also see a number of other improvements that simply didn’t exist on the original 8088.

The Rise of 32-bit Processing

The old 8088 had 16-bit registers, an 8-bit EDB, and a 20-bit address bus. Old operating systems (such as DOS and early versions of Windows) were written to work on the 8088. Over the years, later CPUs gradually increased their address buses and general-purpose register sizes to 32 bits, allowing much more powerful operating systems (such as Linux, Windows XP, and Windows Vista) to work with the Pentium to process larger numbers at a single time and to address up to 232 = 4,294,967,296 = 4 gigabytes of RAM (see Figure 5-26). Running 32-bit operating systems on 32-bit hardware is called 32-bit processing.

Figure 5-26 A 32-bit register

Both AMD and Intel now make 64-bit processors that address up to 264 = 18,446,744, 073,709,551,616 bytes of RAM. To take advantage of this larger address bus, a 64-bit version of the operating system must be used. You’ll learn more about 64-bit processors later in this chapter.

Pipelining

Remember earlier