public float TargetFrameTimeVarianceMs { get; set; }

When the rolling variance rises above this value the provider asks the indexer to decrease scaler quality. When it falls below a quarter of this value (equivalent to half the corresponding standard deviation) the provider asks for an increase. The band in between provides hysteresis so the system does not oscillate around the target.

The signal the variance is measured on depends on presentation timing. When frames are presented on a fixed display cadence — vsync, or any mobile compositor — wall-clock frame time quantizes to that cadence and masks instability, so the provider measures variance on CPU and GPU work time instead. Otherwise it measures variance on wall-clock frame time directly. For the full behavior of this mode, refer to AdaptivePerformanceStableFrameModeProvider.

As a rule of thumb the value is roughly the square of the tolerated standard deviation in ms: the default of 16 corresponds to about 4 ms of jitter.