you should use hw.physicalcpu instead of hw.logicalcpu. the former gives the count of cores, the latter the number of virtual cores (physical + hyperthreading). so if you have a system with 2 physical cores and hyperthreading, you'll currently use 4 cores, which increases cpu usage, but doesn't improve performance over 2 cores because of all the context switching.

Will fix, thanks for the good advice