In the present paper, the models of structural analysis and evaluation of efficiency indicators (reliability, fault tolerance, viability, and flexibility) of a multi core processor with variable structure, equipped with multi functional cores, are considered. Using logical probabilistic methods, the following has been developed: models for evaluating the reliability and fault tolerance of processor cores as multi functional elements; logical probabilistic models of the shortest paths, flexibility, and performance conditions for successful operation of multi core processors based on multi functional cores; and models for estimating the reliability, fault tolerance, and lifetime of multi core processors considering all possible states of performance. The results of the structural analysis of two core and four core processors and the trends of increasing the efficiency indicators of multi core processors are presented.