CPU chips or central processing unit chips are used in digital computers and are the semiconductor component where most calculations take place. Specifications include clock speed, internal register size, data input/output (I/O) bus width, memory address bus width, and maximum memory. Today, there are two main manufacturers of CPU chips: Intel and Advanced Micro Devices (AMD). Customers can buy computer chips from these companies directly, or through their networks of distributors. Current and former suppliers of CPU chips also include companies such as Compaq, Digital Electronics Corporation (DEC), Hewlett-Packard (HP), International Business Machines (IBM), Motorola, Transmeta, Samsung, Texas Instruments, and Sun Microsystems. Intel manufacturers many different types of CPU chips. The company’s past and present product lines are the Intel 386, Intel 486, Celeron, Itanium, Pentium, and XScale. Intel 386 and Intel 486 CPU chips have an internal register size and data I/O bus width of 32 bits. Intel Itanium 2 processors are second-generation Itanium chips that are designed for dual processor (DP) and multiprocessor (MP) servers and workstations. Intel’s Pentium line consists of the Pentium, Pentium II, Pentium III, Pentium 4 Prescott, and Pentium M central processing units. The Pentium 4 Prescott CPU is designed to run office and home entertainment software at faster speeds. The Intel Pentium M chip is designed for mobile applications. The Intel Celeron is part of the company’s value line, while Intel XScale CPU chips designed for low power consumption and high performance processing for a wide range of wireless and networking applications. There are four product lines of AMD CPU chips: Athlon, Duron, Opteron, AMD-K6 and Geode. CPU chips in the Athlon family feature an x86 architecture and an on-chip full-speed cache of 384 KB, a system bus speed of 200 MHz, three floating-point pipelines, and a processor bus speed of 200 MHz. Duron CPU chips also use an x86 architecture, three floating-point pipelines, and a system bus speed of 200 MHz. Unlike Athlon products, however, Duron chips have an on-chip full-speed cache of 192 KB. AMD Opteron CPU chips are designed for a 64-bit server line. AMD-K6 chips use multi-media extensions (MMX) and 3DNOW! Technology. There are several members of the AMD Geode family, including the GX1, GXLV, and GXM.