cpuid

The CPUID application is a program that provides in-depth information about the user's CPU(s) and determines the exact model of said CPU(s). As the name suggests, CPUID stands for Central Processing Unit Identifier. In the earlier days of x86 computing, there were vast differences in hardware inside PCs, making it difficult for programmers to identify the hardware the program was running on, let alone take full advantage of its unique features. The CPU was one such area where programs were not optimised based on the user's CPU. Intel recognised this and developed the CPUID instruction.

The CPUID instruction gave instant access to the programmer to a lot of information about the CPU, such as the manufacturer (Intel, AMD, Cyrix, etc.), any "extra features" it supports (FPU, MMX, 3DNow, etc.), and other information. The instruction is generally supported by all CPUs available today, and a complete list of CPUs that support CPUID is provided. However, if the CPU does not support CPUID, calling it to find CPU information may cause the program to crash.

Fortunately, the process for finding out as much information as possible from any given CPU type is provided in flow-chart form, assuming the user is using at least a 386 processor. The latest release of CPUID includes new features such as the -i option being made default due to the unreliable CPUID kernel module, the -k option for users who prefer the previous behaviour, and the ability for the i386 build to work on x86_64 systems. Additionally, CPUID now includes knowledge of Tulsa and pre-production Woodcrest, and properly distinguishes Smithfield Pentium D and Pentium EE from each other.

Overall, CPUID is a useful application for users who want detailed information about their CPU(s) and its unique features, and allows for programs to be optimised based on the user's CPU.