Microprocessor frequency specifies the operating (internal) frequency of CPU's core. The higher the frequency is for a given CPU family, the faster the processor is. Processor frequency is not the only parameter that affects system performance. Another parameter than greatly affects the performance is CPU efficiency, that is how many Instructions Per Clock (IPC) the CPU can process. Knowing these two parameters it's easy to calculate total number of instructions per second that can be processed by CPU: Frequency * IPC. All modern AMD x86 microprocessors and all Intel microprocessors based P6, mobile and Core micro-architectures tried to improve their performance by improving the IPC, and, whenever possible, by increasing processor frequency. Intel Netburst microarchitecture used quite different approach - it tried to increase processor frequency at the expense of IPC. This didn't work well for this micro-architecture.