The present study sought to explore the effects of Multimedia Computer-Assisted Language Learning (MCALL) programs drawing on two different text modalities on the vocabulary retention of Iranian EFL learners. The two groups under study received treatment on vocabulary items under two multimedia conditions: The first group received treatment on the vocabulary items using a multimedia environment comprising streaming video and visual texts, and the second group received treatment on the same items through a similar environment drawing on streaming video and spoken texts. After the experiment, the two groups took an immediate post-test and a delayed post-test. The study revealed that those students who received treatment on the items through visual texts and video outperformed the ones who received treatment on the same items through spoken texts and video. This appears not to corroborate the view that the modularity of the working memory always results in a more efficient learning.