You don't say what analysis you are performing. You say Workbench is so slow, compared with what? Which part of the overall workflow do you find slow, is it waiting for the solution to compute? There are ways to reduce the time spent waiting for a solution that involved making a model that is more efficient at giving you the answer you want. Going from 3D to 2D or changing from Solid elements to Shell elements. You don't say how many GB of RAM is in your computer. The Solver Output from a Structural model will say how much RAM was required for the model you solved. If you don't have enough RAM, you might be able to increase that to speed up the solve time.