They are different in computational approach and efficiency.
The primary distinction between GCV and Parallel GCV is in their computational approach. While both solvers aim to achieve the same solution, the Parallel GCV leverages multiple CPUs to process different parts of the model simultaneously, which significantly accelerates the calculation process.
Although the core algorithm of Parallel GCV is adapted to facilitate parallel computations, the fundamental principles remain consistent with GCV. However, due to the nature of parallel processing, there might be minor discrepancies in the results, computation times, and the number of iterations required for convergence.
Moreover, the recently introduced ParallelGCV-AMG incorporates an advanced multi-grid solver that further enhances the efficiency of calculations, offering even faster processing capabilities.