Background, Motivation and Objective The design of sparse arrays is usually linked to optimization algorithms, based on simulated annealing (SA), to find the set of active elements yielding the best-achievable beam pattern. The computational load of such algorithms is high and, according to SA theory, the quality of the results increases with the number of iterations. Considering 2D array optimization, an acceptable solution is generally reached after several thousand iterations. Besides, realistic acoustic simulations improve the probe design but make the computation time even longer (up to a few days). In this work, we propose to speed-up the optimization process by 1) introducing a fast pressure field (PF) update algorithm, and 2) a method to reduce the number of pressure measurement points (PMPs).