Parallel lets you run Stata faster, sometimes faster than MP itself. By organizing your job in several Stata instances, parallel allows you to work with out-of-the-box parallel computing. Using the the parallel prefix, you can get faster simulations, bootstrapping, reshaping big data, etc. without having to know a thing about parallel computing. With no need of having Stata/MP installed on your computer, parallel has showed to dramatically speedup computations up to two, four, or more times depending on how many processors your computer has.
More details here