Yes I did notice that 8 perl processes vs 1 "only" sped things up about 3.5x. Tests show no gains over 4 workers here. I guess these i7 processors have 4 physical cores virtualized to 8 marketing thingies. Without MCE my computationally intensive code seemed to be using the resources of 1/2 of 1 of the four real cores (1 virtual core? teenage CPU %s). MCE appears to unlock the missing ~85% of my CPU power. It's like I downloaded 3.5 more of these 4k computers from CPAN for FREE with MCE (and 1 post++ from Perlmonk vr): A $14,000 value! Unreal...