CPUsyklusen

CPUsyklusen, or CPU cycle, is the basic timing unit that governs when a central processing unit can perform work. In a synchronous CPU, one cycle is the interval defined by the processor’s clock signal; the clock frequency determines how many cycles occur each second. The concept provides a coarse timing framework for coordinating instruction fetch, decode, execution, and write-back.

In practice, modern CPUs use deep pipelines, multiple execution units, and out-of-order execution. An individual instruction often spans several cycles, and several instructions can be processed in parallel at different stages of the pipeline. The average number of cycles required to complete an instruction is called cycles per instruction (CPI) and varies with the microarchitecture and workload.

Clock speed, measured in hertz (GHz, MHz), indicates potential throughput but does not alone guarantee higher performance. CPI penalties from cache misses, branch mispredictions, or memory latency can offset higher frequencies. Power consumption also rises with frequency, since dynamic power scales with frequency and voltage.

Modern processors may employ dynamic frequency scaling, such as turbo or boost modes, to temporarily increase the cycle rate on active cores while managing heat and energy use. Performance is therefore a function of both the cycle rate and the processor’s ability to keep its pipeline efficiently fed.

CPUszyklener are commonly evaluated using metrics like instructions per cycle (IPC) and benchmark scores, rather than clock speed alone. While architectures differ in their pipeline design and timing, the basic idea remains: faster cycles can enable more work per second, provided execution remains efficient.