CST - CPU never at 100% (CST Studio Suite)

Anyone knows why while CST high frequency solver is running, CPU is not at 100% in charge?? Why this waste of resources??
Idem if you use CPU+GPU. Neither is ever 100% :((((((((((((((((((((((((
Rig: Dual Xeon E5-2687W-v4 + Quadro GP100

CPU is about 57%. it's very frustrating !!!!!

THANKS!!

CST Studio Suite ​​​​​​​