Glossary/CPU/Single-core performance
Single-core performance
Single-core performance is how much work one CPU core completes on its own, and it governs responsiveness in games and most interactive software.
Also known as single-thread performance, ST performance
Measured by SystemCheck
Part of the four-stage run: a 60-second sustained CPU load reporting throughput, decay and consistency; a memory stage reporting bandwidth and latency; a GPU raster load at a fixed resolution reporting frame rate, pacing and decay; and a path tracer reporting samples per second. The paragraphs below say which metric carries this term.
A large fraction of everyday software has a critical path that cannot be parallelised. Game simulation and main render threads, JavaScript execution, spreadsheet dependency chains, and most application startup are limited by how fast one core is. Adding cores does nothing for them.
Single-core performance is IPC times sustained single-core frequency. It is also the metric where thermal state matters least, because one active core rarely pushes a system to its power or thermal ceiling, so single-core numbers are relatively stable between a cold and a hot machine, unlike all-core numbers.
In SystemCheck, the contrast between single-thread behaviour and the all-core result is diagnostic. A machine with strong single-core throughput and weak multi-core throughput is usually power- or thermally-limited under load. A machine weak on both is more likely limited by generation, memory latency, or heavy background contention.
A useful way to see it on your own machine is to compare how responsive the system feels with how it scores under an all-core load. If everyday work feels quick but long exports are slow, single-core speed is fine and the limit is sustained all-core behaviour. If opening apps and loading pages feel slow too, single-core speed or background load is the place to look, and closing background work before a test is the first check.
Related terms