Sampling gaps and unavailable sensors

Chart history describes observations, not continuous knowledge of the Mac. Use the horizontal time axis and availability labels before comparing values or drawing a conclusion about an interval.

Reading states

What you see	What it supports	What it does not establish
A plotted sample	A reading at its observation time	That the same value held until the next sample
A gap between observations	Missing measurements in that interval	Zero CPU, no traffic or a healthy service
An unavailable sensor	This reading was not supplied	An idle component or a broken component
No battery information	Battery information is not present for this hardware	A battery at zero charge
A current process row	The process was observed in the current table	Application-level health

Time ranges

CPU and Memory focus offer 15 seconds, 30 seconds, 1 minute and 2 minutes. These are viewing ranges, not promises of complete samples at every instant. Compare actual observation times across ranges. Do not infer a sampling cadence from a screenshot, and do not interpolate across a missing interval when reporting an incident.

Hardware-dependent readings

Battery information appears only when a battery exists. Temperature and fan readings depend on hardware support. A missing sensor should stay unavailable in notes and support reports; replacing it with zero changes the meaning of the evidence.

Resource and service evidence differ

Machine-resource histories answer a monitoring question. A controller service record answers attribution and supervision questions. A configured health check that actually ran answers a narrower service-health question. If one of those observations is stale or absent, another does not fill the gap.

When a reading surprises you, return to Quick View and timed charts, confirm the destination and time range, then record the label you actually saw. The maintained application documentation is the primary reference for available chart ranges and hardware limitations.