Background: Video on demand (VoD) is a fast-growing digital service that requires a substantial amount of hardware resources for its implementation. To reduce the costs of running this service, an alternative is to use proxies that cache the most important portions of the video collection in order to meet the demand for this content in place of the primary server of the VoD system. Methods: To improve the efficiency of the proxies, we proposed a novel caching algorithm that explores the positioning of the active clients to determine the density of clients inside a time window existing in front of each video chunk. The algorithm attributes a higher caching priority to the video chunks with greater aggregate density in the memory. To evaluate our approach, we compared it with others of similar nature using both traditional metrics like hit ratio, as well as physical metrics such as the use of processing resources. This complementary set of metrics is produced by our simulator that, as far as we know, is the first one of its kind to enable the evaluation of hardware consumption used to implement the VoD proxy. Results: Results show that the novel algorithm can achieve a higher hit ratio while requiring a little more effort from the hardware. Additionally, it was identified that the processor constitutes the major bottleneck to this application when demand increases. Conclusions: Among the recent emergence of caching strategies which consider the positioning of clients as criterion for caching, the strategy of prioritizing the chunks with greater density of previous clients showed to be a more efficient solution.