Dynamois a package for the processing of tomographic data. As a tool for subtomogram averaging, it includes different alignment and classification strategies. Furthermore, its data-management module allows experiments to be organized in groups of tomograms, while offering specialized three-dimensional tomographic browsers that facilitate visualization, location of regions of interest, modelling and particle extraction in complex geometries. Here, a technical description of the package is presented, focusing on its diverse strategies for optimizing computing performance.Dynamois built upon mbtools (middle layer toolbox), a general-purposeMATLABlibrary for object-oriented scientific programming specifically developed to underpinDynamobut usable as an independent tool. Its structure intertwines a flexibleMATLABcodebase with precompiled C++ functions that carry the burden of numerically intensive operations. The package can be delivered as a precompiled standalone ready for execution without aMATLABlicense. Multicore parallelization on a single node is directly inherited from the high-level parallelization engine provided forMATLAB, automatically imparting a balanced workload among the threads in computationally intense tasks such as alignment and classification, but also in logistic-oriented tasks such as tomogram binning and particle extraction.Dynamosupports the use of graphical processing units (GPUs), yielding considerable speedup factors both for nativeDynamoprocedures (such as the numerically intensive subtomogram alignment) and procedures defined by the user through itsMATLAB-based GPU library for three-dimensional operations. Cloud-based virtual computing environments supplied with a pre-installed version ofDynamocan be publicly accessed through the Amazon Elastic Compute Cloud (EC2), enabling users to rent GPU computing time on a pay-as-you-go basis, thus avoiding upfront investments in hardware and longterm software maintenance.