Dependence of QPE detection on the eruptions-to-quiescence temperature ratio. The relative 0.2-2 keV QPE amplitude is shown as a function of the ratio of QPE to quiescent temperatures. The horizontal shaded area denotes the region below the QPE detection threshold. Also shown (black data point) is the strongest X-ray flare seen in any observation with no clearly detected QPEs. The dotted line shows a simple fit to the data, whose functional form is chosen so that A_rel = 1 when kT_QPE/kT_quiesc = 1 (see text for details).