Fluorescence sensitivity in Cytometry defines the instrument’s ability to fully resolve populations carrying close and small levels of fluorescence. Sensitivity can be measured in a descriptive manner, via resolution score parameters taking into account not only the difference between peaks means, but also the degree of dispersion associated with each peak distribution. In addition to the intrinsic and illumination contributions to signal dispersion, the stochastic nature of the photon counting process at each detector invariably contributes to dim peak spreading with a resultant resolution loss at the low signal end. In Cytometry theory, resolution between dim peaks can be predicted as a function of the number of fluorescent molecules carried by each peak, the instrument quantum efficiency and overall background. Instruments with low fluorescence sensitivity have small quantum efficiencies, high background or a combination of both. Here we present the preliminary results from a pilot benchmark study where the sensitivity of cytometers from several manufacturers including bench-top analysers, cuvette-based and jet-in-air cell sorters was evaluated via the resolution of dim Rainbow 8 peak beads, detectors quantum efficiency and background calculations. Results gathered at this point provide a comprehensive analysis of existing platforms, the detection of performance outliers, exploring strategies to boost instrument performance as well as a basis for the evaluation of emerging technologies.