为什么两个相似CPU的同一程序的执行时间不同？

I am trying to figure out why does program (code below) runs faster using two treads instead of four on Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz but on Intel(R) Core(TM) i7-4510U CPU @ 2.00GHz four thread version runs faster than two thread version of the same program.I am trying to figure out why does program (cod