>A regular Fox app cannot take advantage of multiprocessors. However, an MTDLL can.

Just to expand a bit on Craig's comments, VFP is for a dev's purposes single-threaded, though VFP will have anywhere from 2 to 4 threads (you can't use more than one of them, though).

As Craig points out, VFP multi-threaded COM DLLs will utilize multi-procs. Depending on what you're doing, you may have synchronization issues to watch for.