The number of verbal items which can be recalled immediately is related to the rate at which an individual can speak. Subvocal rehearsal, or articulatory recoding in working memory, has been assumed to mediate this relation. For spatial items recalled in order there is also a relationship with articulation rate, which is not related to verbal rehearsal of the items. One reason for this might be that the relationship is mediated by speed of memory scanning for serial position tags in a memory set, which is related to processing speed. Subjects were asked to perform visuospatial memory tasks which involved serial position and visuospatial memory tasks in which serial position was not involved. They also performed a digit span task. The results indicated that the visuospatial memory tasks were highly related, that they were only weakly related to digit span, and that articulation rate was correlated with every measure of memory performance used, whether serial position was involved or not. There is no support for the hypothesis that speed of scanning for serial position information in immediate spatial memory leads to a relationship with articulation rate, nor is there any support for the view that memory span tasks in different domains share resources for dealing with serial order. The results are discussed in relation to Cowan, Keller, Hulme, Roodenrys, McDougall & Rack's (1994) suggestion that the relationship between articulation rate and memory span may be mediated by general processing speed.