[firedrake] Why is firedrake so fast?

Hi all, So I have some personal computers which will give me roughly the same serial performance (in terms of wall-clock time) as a single compute node (via interactive mode e.g., salloc -N 1 -n 16) at one of LANL's machines (Intel Xeon E5 2670). However, once I submit my firedrake program as a job script (via MOAB) to said LANL machine, the performance becomes 10x faster! Certainly not complaining, but I find this unusual. I never encountered such a performance improvement if I were to submit a normal PETSc program. Does this have something to do with the internal framework of firedrake? I can provide more information as needed Thanks, Justin