Frame time
Frame time is the milliseconds taken to produce one frame, and it describes smoothness far more accurately than an averaged frames-per-second figure.
Also known as frametime, ms per frame
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.
Frame rate is the reciprocal of the average frame time, and averaging destroys the information that matters. A run that alternates 8 ms and 25 ms frames averages to a comfortable-looking 60 fps while feeling visibly jerky. Looking at frame times directly makes the stutter obvious.
Frame time is also a linear scale where fps is not. Going from 30 to 60 fps saves 16.7 ms per frame; going from 120 to 144 fps saves 1.4 ms. That is why chasing headline fps numbers past a point yields so little perceptual return, and why competitive players talk in milliseconds.
SystemCheck's GPU raster stage records per-frame timings rather than a single averaged rate, and derives stability and decay from that distribution. This is what lets a report distinguish a GPU that is slow but even from one that is fast on average but delivers frames unevenly, two very different problems with different fixes.
Related terms