The main focus of state-of-the-art works in RF power amplifier digital predistortion is to improve the linearity of the system, but studying the energy efficiency of the amplifiers is normally omitted. When used in massive MIMO antenna arrays, besides of the power amplifier nonlinear behavior, crosstalk between transmitter chains further reduce signal quality. The problem on how to linearize the PA's, and at the same time mitigate the cross-talks while achieving maximum energy efficiency raises. In this work, using a joint linearity-efficiency PA model based on a generic transistor and a physically inspired model of the antenna array crosstalk, the relationship between linearity, power added efficiency and crosstalk is investigated. Assuming a full-digital architecture, the SISO case and three MIMO cases are considered: a reference model with a single PA, 2 transmitters, a linear array of 5 transmitters, and a square array of 5x5 transmitters. Digital predistortion is reformulated as a constrained optimization problem, and a solution for the simulated systems found using an interior-point method. A pruned DPD architecture is used to reduce the number of parameters. The results show that the point of maximum linearity does not match the point of maximum efficiency, under signal quality constraints.