Step 3 takes for ever… this machine shoul fly. Any suggestions?
I see you are using a Quadro graphics card. Could you look at this article? Long Processing Time for Step 3 with Quadro GPUs.
Also, keep in mind that all processing steps use the computer resources differently, so ensure you have a balanced components composition to avoid bottle necks. And even within a step, it happens that some small instructions need to be completed, which cannot be paralleled and therefore it will not use the full resources. See Hardware components usage when processing with Pix4D.
Processing time is related to the number of images, their resolution, size, content (features in them), and the overlap between them. See Processing speed.
Let me know if it helps