Small columns packed with core–shell and sub-2μm totally porous particles and monolith columns are very popular to conduct fast and efficient chromatographic separations. In order to carry out fast separations, short (2–5cm) and narrow-bore (2–2.1mm) columns are used to decrease the analyte retention volume. Beside the column efficiency, another significant issue is the extra-column band-spreading. The extra-column dispersion of a given LC system can dramatically decrease the performance of a small very efficient column. The aim of this study was to compare the extra-column peak variance contribution of several commercially available LC systems. The efficiency loss of three different type 5cm long narrow bore, very efficient columns (monolith, sub-2μm fully porous and sub-2μm core–shell packing) as a function of extra-column peak variance, and as a function of flow rate and also kinetic plots (analysis time versus apparent column efficiency) are presented.