Glossary/System/Background load contamination
Background load contamination
Background load contamination is other software consuming CPU, GPU, or memory during a benchmark, depressing and destabilising the result.
Also known as background interference, benchmark contamination
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 calibrated GPU raster load reporting frame time, pacing and decay; and a path tracer reporting samples per second. The paragraphs below say which metric carries this term.
Windows Update, antivirus scans, cloud sync clients, browser tabs, game launchers, and RGB utilities all take resources without asking. A single background thread on a heavily loaded machine can cost several percent, and a scan starting mid-run produces a result that looks like a throttling problem but is not.
The signature is poor consistency with acceptable peak throughput: the machine is fast when nothing interferes and stalls when something does. That pattern is easy to confuse with thermal cycling, which is why the first diagnostic step for any surprising result should be closing everything and re-running.
This is especially relevant for a browser benchmark, where other tabs share the same process tree and GPU. Close other tabs, pause sync clients, and let the machine idle for a minute before running SystemCheck. SystemCheck's consistency figure is the metric most sensitive to contamination. A large improvement on a clean re-run tells you the first result was contaminated rather than the hardware being at fault.
Related terms